diff --git a/src/core/Akka.Tests/Actor/ActorRefSpec.cs b/src/core/Akka.Tests/Actor/ActorRefSpec.cs
index 0cb77f298db..05d012521ad 100644
--- a/src/core/Akka.Tests/Actor/ActorRefSpec.cs
+++ b/src/core/Akka.Tests/Actor/ActorRefSpec.cs
@@ -12,6 +12,7 @@
 using Akka.Serialization;
 using Akka.TestKit;
 using Akka.TestKit.TestActors;
+using Akka.Util;
 using Xunit;
 
 namespace Akka.Tests.Actor
@@ -290,6 +291,16 @@ public void An_ActorRef_should_never_have_a_null_Sender_Bug_1212()
             ExpectNoMsg();
         }
 
+        [Fact]
+        public void An_ActorRef_Mock_should_be_like_Nobody()
+        {
+            var mock = new ActorRefMock();
+
+            mock.Tell("dummy");
+
+            mock.IsNobody().ShouldBeTrue();
+        }
+
         private void VerifyActorTermination(IActorRef actorRef)
         {
             var watcher = CreateTestProbe();
@@ -297,6 +308,37 @@ private void VerifyActorTermination(IActorRef actorRef)
             watcher.ExpectTerminated(actorRef, TimeSpan.FromSeconds(20));
         }
 
+        private sealed class ActorRefMock : IActorRef
+        {
+            public ActorRefMock() { }
+
+            ActorPath IActorRef.Path => null;
+
+            int IComparable<IActorRef>.CompareTo(IActorRef other)
+            {
+                throw new NotSupportedException();
+            }
+
+            int IComparable.CompareTo(object obj)
+            {
+                throw new NotSupportedException();
+            }
+
+            bool IEquatable<IActorRef>.Equals(IActorRef other)
+            {
+                throw new NotSupportedException();
+            }
+
+            void ICanTell.Tell(object message, IActorRef sender)
+            {
+            }
+
+            ISurrogate ISurrogated.ToSurrogate(ActorSystem system)
+            {
+                throw new NotSupportedException();
+            }
+        }
+
         private class NestingActor : ActorBase
         {
             internal readonly IActorRef Nested;
diff --git a/src/core/Akka/Actor/ActorRef.Extensions.cs b/src/core/Akka/Actor/ActorRef.Extensions.cs
index e876d9744a4..ef4be2f9988 100644
--- a/src/core/Akka/Actor/ActorRef.Extensions.cs
+++ b/src/core/Akka/Actor/ActorRef.Extensions.cs
@@ -23,7 +23,8 @@ public static class ActorRefExtensions
         /// <returns><c>true</c> if the <paramref name="actorRef"/> is valid; otherwise <c>false</c>.</returns>
         public static bool IsNobody(this IActorRef actorRef)
         {
-            return actorRef == null || actorRef is Nobody || actorRef is DeadLetterActorRef || (actorRef.Path.Uid == 0 && actorRef.Path.Name == "deadLetters");
+            return actorRef is null || actorRef is Nobody || actorRef is DeadLetterActorRef 
+                || actorRef.Path is null || (actorRef.Path.Uid == 0 && actorRef.Path.Name == "deadLetters");
         }
 
         /// <summary>