diff --git a/include/etl/private/delegate_cpp11.h b/include/etl/private/delegate_cpp11.h
index 33d993e2..9664797b 100644
--- a/include/etl/private/delegate_cpp11.h
+++ b/include/etl/private/delegate_cpp11.h
@@ -172,7 +172,7 @@ namespace etl
     //*************************************************************************
     // Construct from a function pointer.
     //*************************************************************************
-    delegate(function_ptr fp) ETL_NOEXCEPT
+    explicit delegate(function_ptr fp) ETL_NOEXCEPT
     {
       assign(fp, function_ptr_stub);
     }
@@ -534,7 +534,14 @@ namespace etl
     //*************************************************************************
     delegate& operator=(function_ptr fp) ETL_NOEXCEPT
     {
-      assign(fp, function_ptr_stub);
+      if (fp == ETL_NULLPTR)
+      {
+        invocation.clear();
+      }
+      else
+      {
+        assign(fp, function_ptr_stub);
+      }
       return *this;
     }
 
diff --git a/test/test_delegate.cpp b/test/test_delegate.cpp
index b8445166..d57ad1f8 100644
--- a/test/test_delegate.cpp
+++ b/test/test_delegate.cpp
@@ -372,6 +372,27 @@ namespace
       CHECK_FALSE(d.is_valid());
     }
 
+    //*************************************************************************
+    TEST_FIXTURE(SetupFixture, test_is_valid_after_init_empty_braces)
+    {
+      etl::delegate<void(void)> d = {};
+
+      CHECK_FALSE(d.is_valid());
+    }
+
+    //*************************************************************************
+    TEST_FIXTURE(SetupFixture, test_is_valid_after_assign_empty_braces)
+    {
+      auto lambda = [] {
+      };
+
+      etl::delegate<void(void)> d(lambda);
+
+      CHECK_TRUE(d.is_valid());
+      d = {};
+      CHECK_FALSE(d.is_valid());
+    }
+
     //*************************************************************************
     TEST_FIXTURE(SetupFixture, test_free_void)
     {