diff --git a/openmp/libomptarget/DeviceRTL/include/Interface.h b/openmp/libomptarget/DeviceRTL/include/Interface.h
index 1a8471a2352f..027d2c9e1364 100644
--- a/openmp/libomptarget/DeviceRTL/include/Interface.h
+++ b/openmp/libomptarget/DeviceRTL/include/Interface.h
@@ -198,6 +198,9 @@ void __kmpc_end_sharing_variables();
 /// Called by the worker threads in the parallel region (function).
 void __kmpc_get_shared_variables(void ***GlobalArgs);
 
+/// External interface to get the thread ID.
+uint32_t __kmpc_get_hardware_thread_id_in_block();
+
 /// Kernel
 ///
 ///{
diff --git a/openmp/libomptarget/DeviceRTL/src/Mapping.cpp b/openmp/libomptarget/DeviceRTL/src/Mapping.cpp
index 3bd055322cfb..ee2aeeea4700 100644
--- a/openmp/libomptarget/DeviceRTL/src/Mapping.cpp
+++ b/openmp/libomptarget/DeviceRTL/src/Mapping.cpp
@@ -226,4 +226,9 @@ bool mapping::isSPMDMode() { return IsSPMDMode; }
 bool mapping::isGenericMode() { return !isSPMDMode(); }
 ///}
 
+extern "C" {
+uint32_t __kmpc_get_hardware_thread_id_in_block() {
+  return mapping::getThreadIdInBlock();
+}
+}
 #pragma omp end declare target