diff --git a/include/gsl/gsl_thread b/include/gsl/gsl_thread
index afe9ad5..f3f760a 100644
--- a/include/gsl/gsl_thread
+++ b/include/gsl/gsl_thread
@@ -47,13 +47,13 @@ public:
 	detached_thread(detached_thread&& other): t(std::move(other.t)) {}
 
 	detached_thread(std::thread const&) = delete;
-	detached_thread(std::thread&& other) noexcept: t(std::move(other)) { t.detach(); }
+	detached_thread(std::thread&& other) noexcept: t(std::move(other)) { if(t.joinable()) t.detach(); }
 
 	detached_thread& operator=(detached_thread const&) = delete;
 	detached_thread& operator=(detached_thread&& other) noexcept { t = std::move(other.t); return *this; }
 
 	detached_thread& operator=(std::thread const&) = delete;
-	detached_thread& operator=(std::thread&& other) noexcept { t = std::move(other); t.detach(); return *this; }
+	detached_thread& operator=(std::thread&& other) noexcept { t = std::move(other); if(t.joinable()) t.detach(); return *this; }
 
 	template<typename Callable, typename... Args>
 	explicit detached_thread(Callable&& f, Args&&... args)
diff --git a/tests/thread_tests.cpp b/tests/thread_tests.cpp
index 3b85df0..01f1db3 100644
--- a/tests/thread_tests.cpp
+++ b/tests/thread_tests.cpp
@@ -199,6 +199,23 @@ SUITE(detached_thread_tests)
         CHECK(t1.get_id() == id1);
         CHECK(t2.get_id() == id2);
     }
+
+    TEST(detached_thread_ctor_from_detached_std_thread)
+    {
+        std::thread t{[&]{ sleep_for(t_100ms); }};
+        t.detach();
+        gsl::detached_thread{std::move(t)};
+        sleep_for(t_100ms * 2);
+    }
+
+    TEST(detached_thread_assign_from_detached_std_thread)
+    {
+        std::thread t1{[&]{ sleep_for(t_100ms); }};
+        t1.detach();
+        gsl::detached_thread t2;
+        t2 = std::move(t1);
+        sleep_for(t_100ms * 2);
+    }
 }
 
 int main() { return UnitTest::RunAllTests(); }
diff --git a/tests/unittest-cpp b/tests/unittest-cpp
index dc6b908..6d3cc12 160000
--- a/tests/unittest-cpp
+++ b/tests/unittest-cpp
@@ -1 +1 @@
-Subproject commit dc6b90838014ab985bf3cd74ac17ad9d00e1fbcb
+Subproject commit 6d3cc12eab7e4e18c2058acccd467acea4bcd79b