diff --git a/.circleci/config.yml b/.circleci/config.yml
index 40d8bdb90..90b3e2da8 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -803,7 +803,7 @@ jobs:
       - run:
           name: Set branch parent commit env var
           command: |
-            echo "export PARENT_COMMIT=$(git rev-parse "$(git rev-list --topo-order --reverse HEAD ^origin/develop | head -1)"^)" >> $BASH_ENV
+            echo "export PARENT_COMMIT=$(git merge-base origin/HEAD HEAD)" >> $BASH_ENV
             source $BASH_ENV
       - run:
           name: build:announce