diff --git a/git-gui.sh b/git-gui.sh
index 89f636f49..e133331ef 100755
--- a/git-gui.sh
+++ b/git-gui.sh
@@ -3015,6 +3015,7 @@ blame {
 
 		if {$is_path} {
 			if {$path ne {}} usage
+			set path [normalize_relpath $_prefix$a]
 			break
 		} elseif {$a eq {--}} {
 			if {$path ne {}} {