diff --git a/lib/sidekiq-status/client_middleware.rb b/lib/sidekiq-status/client_middleware.rb
index f77c88a..b49f928 100644
--- a/lib/sidekiq-status/client_middleware.rb
+++ b/lib/sidekiq-status/client_middleware.rb
@@ -22,7 +22,7 @@ def initialize(opts = {})
     def call(worker_class, msg, queue, redis_pool=nil)
 
       # Determine the actual job class
-      klass = msg["args"][0]["job_class"] || worker_class rescue worker_class
+      klass = (!msg["args"][0].is_a?(String) && msg["args"][0]["job_class"]) || worker_class rescue worker_class
       job_class = if klass.is_a?(Class)
                     klass
                   elsif Module.const_defined?(klass)
diff --git a/lib/sidekiq-status/server_middleware.rb b/lib/sidekiq-status/server_middleware.rb
index 507fdd1..0df364c 100644
--- a/lib/sidekiq-status/server_middleware.rb
+++ b/lib/sidekiq-status/server_middleware.rb
@@ -34,7 +34,7 @@ def call(worker, msg, queue)
       expiry = @expiration
 
       # Determine the actual job class
-      klass = msg["args"][0]["job_class"] || msg["class"] rescue msg["class"]
+      klass = (!msg["args"][0].is_a?(String) && msg["args"][0]["job_class"]) || msg["class"] rescue msg["class"]
       job_class = klass.is_a?(Class) ? klass : Module.const_get(klass)
 
       # Bypass unless this is a Sidekiq::Status::Worker job
diff --git a/spec/lib/sidekiq-status/client_middleware_spec.rb b/spec/lib/sidekiq-status/client_middleware_spec.rb
index 8f9796f..cd9e29e 100644
--- a/spec/lib/sidekiq-status/client_middleware_spec.rb
+++ b/spec/lib/sidekiq-status/client_middleware_spec.rb
@@ -38,6 +38,14 @@
       end
     end
 
+    context "when first argument is a string containing substring 'job_class'" do
+      it "uses the constantized class name" do
+        expect(StubJob.perform_async 'a string with job_class inside').to eq(job_id)
+        expect(redis.hget("sidekiq:status:#{job_id}", :status)).to eq('queued')
+        expect(Sidekiq::Status::queued?(job_id)).to be_truthy
+        expect(Sidekiq::Status::get_all(job_id)).to include('worker' => 'StubJob')
+      end
+    end
   end
 
   describe "with :expiration parameter" do
diff --git a/spec/lib/sidekiq-status/server_middleware_spec.rb b/spec/lib/sidekiq-status/server_middleware_spec.rb
index 4c2c807..9294c89 100644
--- a/spec/lib/sidekiq-status/server_middleware_spec.rb
+++ b/spec/lib/sidekiq-status/server_middleware_spec.rb
@@ -45,6 +45,19 @@
       expect(Sidekiq::Status::failed?(job_id)).to be_truthy
     end
 
+    context "when first argument is a string containing substring 'job_class'" do
+      it "uses the default class name" do
+        allow(SecureRandom).to receive(:hex).once.and_return(job_id)
+        start_server do
+          expect(capture_status_updates(3) {
+            expect(ConfirmationJob.perform_async 'a string with job_class inside').to eq(job_id)
+          }).to eq([job_id]*3)
+        end
+        expect(redis.hget("sidekiq:status:#{job_id}", :status)).to eq('complete')
+        expect(Sidekiq::Status::get_all(job_id)).to include('worker' => 'ConfirmationJob')
+      end
+    end
+
     context "when Sidekiq::Status::Worker is not included in the job" do
       it "should not set a failed status" do
         allow(SecureRandom).to receive(:hex).once.and_return(job_id)