diff --git a/lib/workers/pr/index.js b/lib/workers/pr/index.js
index 28d081b2071a18a11a201f60d25e2a5c83f36d4d..aba4a1a38a3c49a5ff7a8f49182914e391c61828 100644
--- a/lib/workers/pr/index.js
+++ b/lib/workers/pr/index.js
@@ -237,7 +237,7 @@ async function ensurePr(prConfig) {
         logger.debug(
           {
             prTitle,
-            oldPrBody: existingPr.body,
+            oldPrBody: existingPrBody,
             newPrBody: prBody,
           },
           'PR body changed'