diff --git a/.gitlab-ci/search-common-ancestor.sh b/.gitlab-ci/search-common-ancestor.sh
index 76521f402..a7a3ac44c 100755
--- a/.gitlab-ci/search-common-ancestor.sh
+++ b/.gitlab-ci/search-common-ancestor.sh
@@ -11,7 +11,9 @@ ancestor_horizon=28  # days (4 weeks)
 # Limit the fetch to a certain date horizon to limit the amount of data we get.
 # If the branch was forked from origin/master before this horizon, it should
 # probably be rebased.
-git remote add upstream https://gitlab.gnome.org/GNOME/glib.git
+if ! git ls-remote --exit-code upstream >/dev/null 2>&1 ; then
+    git remote add upstream https://gitlab.gnome.org/GNOME/glib.git
+fi
 git fetch --shallow-since="$(date --date="${ancestor_horizon} days ago" +%Y-%m-%d)" upstream
 
 # Work out the newest common ancestor between the detached HEAD that this CI job