diff --git a/autoload/fugitive.vim b/autoload/fugitive.vim
index 9c2bdf7..d37f932 100644
--- a/autoload/fugitive.vim
+++ b/autoload/fugitive.vim
@@ -1516,7 +1516,7 @@ function! s:Log(cmd, line1, line2, ...) abort
   let dir = getcwd()
   try
     execute cd s:fnameescape(s:repo().tree())
-    let &grepprg = escape(s:git_command() + join(map(cmd, '" ".s:shellesc(v:val)'), ''), '%#')
+    let &grepprg = escape(s:git_command() . join(map(cmd, '" ".s:shellesc(v:val)'), ''), '%#')
     let &grepformat = '%Cdiff %.%#,%C--- %.%#,%C+++ %.%#,%Z@@ -%\d%\+\,%\d%\+ +%l\,%\d%\+ @@,%-G-%.%#,%-G+%.%#,%-G %.%#,%A%f::%m,%-G%.%#'
     exe a:cmd
   finally