diff --git a/test/distrib/cpp/run_distrib_test.sh b/test/distrib/cpp/run_distrib_test.sh
index 5c21a1e19ec..dfe9867a602 100755
--- a/test/distrib/cpp/run_distrib_test.sh
+++ b/test/distrib/cpp/run_distrib_test.sh
@@ -30,7 +30,7 @@
 
 set -ex
 
-git clone https://github.com/grpc/grpc.git
+git clone $EXTERNAL_GIT_ROOT
 cd grpc && git submodule update --init
 
 cd third_party/protobuf && ./autogen.sh && \