diff --git a/lua/oil/mutator/preview.lua b/lua/oil/mutator/preview.lua
index 82308c6..93b173c 100644
--- a/lua/oil/mutator/preview.lua
+++ b/lua/oil/mutator/preview.lua
@@ -67,6 +67,7 @@ M.show = vim.schedule_wrap(function(actions, should_confirm, cb)
     style = "minimal",
     border = "rounded",
   })
+  vim.bo[bufnr].filetype = "oil_preview"
   vim.bo[bufnr].syntax = "oil_preview"
 
   local lines = {}