diff --git a/src/main/java/biz/paluch/logging/gelf/GelfMessageAssembler.java b/src/main/java/biz/paluch/logging/gelf/GelfMessageAssembler.java
index 3955f6971..54df19ddd 100644
--- a/src/main/java/biz/paluch/logging/gelf/GelfMessageAssembler.java
+++ b/src/main/java/biz/paluch/logging/gelf/GelfMessageAssembler.java
@@ -197,7 +197,9 @@ private void setupStaticFields(PropertyProvider propertyProvider) {
     }
 
     public void addField(MessageField field) {
-        this.fields.add(field);
+        if (!fields.contains(field)) {
+            this.fields.add(field);
+        }
     }
 
     public void addFields(Collection<? extends MessageField> fields) {
diff --git a/src/main/java/biz/paluch/logging/gelf/wildfly/WildFlyJsonFormatter.java b/src/main/java/biz/paluch/logging/gelf/wildfly/WildFlyJsonFormatter.java
index 0fdd1bc35..d05790a1e 100644
--- a/src/main/java/biz/paluch/logging/gelf/wildfly/WildFlyJsonFormatter.java
+++ b/src/main/java/biz/paluch/logging/gelf/wildfly/WildFlyJsonFormatter.java
@@ -21,6 +21,8 @@
 import biz.paluch.logging.gelf.intern.GelfMessage;
 import biz.paluch.logging.gelf.jboss7.JBoss7JulLogEvent;
 
+import java.util.*;
+
 /**
  * Log-Formatter for JSON using fields specified within GELF. This formatter will produce a JSON object for each log event.
  * Example:
@@ -46,6 +48,8 @@
  * Following parameters are supported/needed:
  * <ul>
  * <li>lineBreak (Optional): End of line, defaults to {@code \n}</li>
+ * <li>fields (Optional): Comma-separated list of log event fields that should be included in the JSON. Defaults to
+ * {@code Time, Severity, ThreadName, SourceClassName, SourceMethodName, SourceSimpleClassName, LoggerName, NDC}</li>
  * <li>originHost (Optional): Originating Hostname, default FQDN Hostname</li>
  * <li>extractStacktrace (Optional): Post Stack-Trace to StackTrace field, default false</li>
  * <li>filterStackTrace (Optional): Perform Stack-Trace filtering (true/false), default false</li>
@@ -76,26 +80,81 @@
  */
 public class WildFlyJsonFormatter extends ExtFormatter {
 
+    public static final String MULTI_VALUE_DELIMITTER = ",";
     private MdcGelfMessageAssembler gelfMessageAssembler = new MdcGelfMessageAssembler();
     private String lineBreak = "\n";
+    private boolean wasSetFieldsCalled = false;
+
+    public static final Set<LogMessageField.NamedLogField> SUPPORTED_FIELDS;
+
+    static {
+        Set<LogMessageField.NamedLogField> supportedFields = new LinkedHashSet<LogMessageField.NamedLogField>();
+
+        supportedFields.add(Time);
+        supportedFields.add(Severity);
+        supportedFields.add(ThreadName);
+        supportedFields.add(SourceClassName);
+        supportedFields.add(SourceMethodName);
+        supportedFields.add(SourceSimpleClassName);
+        supportedFields.add(LoggerName);
+        supportedFields.add(NDC);
+        supportedFields.add(Server);
+
+        SUPPORTED_FIELDS = Collections.unmodifiableSet(supportedFields);
+
+    }
 
     /**
      * Create a new instance of the {@link WildFlyJsonFormatter}.
      */
     public WildFlyJsonFormatter() {
-        gelfMessageAssembler.addFields(LogMessageField.getDefaultMapping(Time, Severity, ThreadName, SourceClassName,
-                SourceMethodName, SourceSimpleClassName, LoggerName, NDC, Server));
+
     }
 
     @Override
     public String format(ExtLogRecord extLogRecord) {
+        if (!wasSetFieldsCalled) {
+            addFields(SUPPORTED_FIELDS);
+        }
+
         GelfMessage gelfMessage = gelfMessageAssembler.createGelfMessage(new JBoss7JulLogEvent(extLogRecord));
-        return gelfMessage.toJson("") + lineBreak;
+        return gelfMessage.toJson("") + getLineBreak();
+    }
+
+    public void setFields(String fieldSpec) {
+
+        String[] properties = fieldSpec.split(MULTI_VALUE_DELIMITTER);
+        List<LogMessageField.NamedLogField> fields = new ArrayList<LogMessageField.NamedLogField>();
+        for (String field : properties) {
+
+            LogMessageField.NamedLogField namedLogField = LogMessageField.NamedLogField.byName(field.trim());
+            if (namedLogField == null) {
+                throw new IllegalArgumentException("Cannot resolve field name '" + field
+                        + "' to a field. Supported field names are: " + SUPPORTED_FIELDS);
+            }
+
+            if (!SUPPORTED_FIELDS.contains(namedLogField)) {
+                throw new IllegalArgumentException("Field '" + field + "' is not supported. Supported field names are: "
+                        + SUPPORTED_FIELDS);
+            }
+
+            fields.add(namedLogField);
+        }
+
+        addFields(fields);
+
+    }
+
+    private void addFields(Collection<LogMessageField.NamedLogField> fields) {
+        gelfMessageAssembler.addFields(LogMessageField.getDefaultMapping(fields
+                .toArray(new LogMessageField.NamedLogField[fields.size()])));
+
+        wasSetFieldsCalled = true;
     }
 
     public void setAdditionalFields(String fieldSpec) {
 
-        String[] properties = fieldSpec.split(",");
+        String[] properties = fieldSpec.split(MULTI_VALUE_DELIMITTER);
 
         for (String field : properties) {
             final int index = field.indexOf('=');
@@ -106,7 +165,7 @@ public void setAdditionalFields(String fieldSpec) {
     }
 
     public void setMdcFields(String fieldSpec) {
-        String[] fields = fieldSpec.split(",");
+        String[] fields = fieldSpec.split(MULTI_VALUE_DELIMITTER);
 
         for (String field : fields) {
             gelfMessageAssembler.addField(new MdcMessageField(field.trim(), field.trim()));
@@ -114,7 +173,7 @@ public void setMdcFields(String fieldSpec) {
     }
 
     public void setDynamicMdcFields(String fieldSpec) {
-        String[] fields = fieldSpec.split(",");
+        String[] fields = fieldSpec.split(MULTI_VALUE_DELIMITTER);
 
         for (String field : fields) {
             gelfMessageAssembler.addField(new DynamicMdcMessageField(field.trim()));
diff --git a/src/site/markdown/examples/wildfly-json.md b/src/site/markdown/examples/wildfly-json.md
index 4922449fd..b9f7fe1d9 100644
--- a/src/site/markdown/examples/wildfly-json.md
+++ b/src/site/markdown/examples/wildfly-json.md
@@ -2,6 +2,8 @@ Settings
 --------------
 Following settings can be used:
 
+ * lineBreak (Optional): End of line, defaults to `\n`
+ * fields (Optional): Comma-separated list of log event fields that should be included in the JSON. Defaults to `Time, Severity, ThreadName, SourceClassName, SourceMethodName, SourceSimpleClassName, LoggerName, NDC`
  * version (Optional): GELF Version 1.0 or 1.1, default 1.0
  * originHost (Optional): Originating Hostname, default FQDN Hostname
  * extractStackTrace (Optional): Post Stack-Trace to StackTrace field, default false
@@ -49,6 +51,7 @@ XML Configuration:
             <properties>
                 <property name="version" value="1.0" />
                 <property name="facility" value="java-test" />
+                <property name="fields" value="Time,Severity,ThreadName,SourceClassName,SourceMethodName,SourceSimpleClassName,LoggerName,NDC" />
                 <property name="extractStackTrace" value="true" />
                 <property name="filterStackTrace" value="true" />
                 <property name="mdcProfiling" value="true" />
@@ -81,6 +84,7 @@ CLI Configuration:
     /subsystem=logging/custom-formatter=JsonFormatter/:add(module=biz.paluch.logging,class=biz.paluch.logging.gelf.wildfly.WildFlyJsonFormatter,properties={ \
            version="1.0", \
 		   facility="java-test", \
+		   fields="Time,Severity,ThreadName,SourceClassName,SourceMethodName,SourceSimpleClassName,LoggerName,NDC", \
 		   extractStackTrace=true, \
 		   filterStackTrace=true, \
 		   mdcProfiling=true, \
diff --git a/src/test/java/biz/paluch/logging/gelf/wildfly/WildFlyGelfLogFormatterTest.java b/src/test/java/biz/paluch/logging/gelf/wildfly/WildFlyGelfLogFormatterTest.java
index 80ca4a50d..181d1f455 100644
--- a/src/test/java/biz/paluch/logging/gelf/wildfly/WildFlyGelfLogFormatterTest.java
+++ b/src/test/java/biz/paluch/logging/gelf/wildfly/WildFlyGelfLogFormatterTest.java
@@ -1,11 +1,7 @@
 package biz.paluch.logging.gelf.wildfly;
 
 import static org.hamcrest.CoreMatchers.containsString;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.*;
 
 import java.io.StringWriter;
 import java.util.Map;
@@ -122,6 +118,38 @@ public void testSimpleWithStringFormatSubstitution() throws Exception {
 
     }
 
+    @Test(expected = IllegalArgumentException.class)
+    public void testUnknownField() throws Exception {
+
+        WildFlyJsonFormatter formatter = new WildFlyJsonFormatter();
+        formatter.setFields("dummy");
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testNotSupportedField() throws Exception {
+
+        WildFlyJsonFormatter formatter = new WildFlyJsonFormatter();
+        formatter.setFields("Marker");
+    }
+
+    @Test
+    public void testFields() throws Exception {
+
+        WildFlyJsonFormatter formatter = new WildFlyJsonFormatter();
+        formatter.setFields("Time,Severity,ThreadName,SourceSimpleClassName,NDC");
+
+        handler.setFormatter(formatter);
+        Logger logger = Logger.getLogger(getClass().getName());
+        logger.addHandler(handler);
+
+        logger.info(LOG_MESSAGE);
+
+        Map<String, Object> message = getMessage();
+
+        assertNotNull(message.get("SourceSimpleClassName"));
+        assertNull(message.get("LoggerName"));
+    }
+
     @Test
     public void testLineBreak() throws Exception {
 
@@ -138,7 +166,7 @@ public void testLineBreak() throws Exception {
     }
 
     @Test
-    public void testFields() throws Exception {
+    public void testMdcFields() throws Exception {
 
         WildFlyJsonFormatter formatter = new WildFlyJsonFormatter();
         formatter.setOriginHost("myhost");