diff --git a/src/benchmark_api_internal.cc b/src/benchmark_api_internal.cc
new file mode 100644
index 0000000..8d31083
--- /dev/null
+++ b/src/benchmark_api_internal.cc
@@ -0,0 +1,15 @@
+#include "benchmark_api_internal.h"
+
+namespace benchmark {
+namespace internal {
+
+State BenchmarkInstance::Run(
+    size_t iters, int thread_id, internal::ThreadTimer* timer,
+    internal::ThreadManager* manager) const {
+  State st(iters, arg, thread_id, threads, timer, manager);
+  benchmark->Run(st);
+  return st;
+}
+
+}  // internal
+}  // benchmark