"git show" does not use diff.external like "git diff" does

I have diff.external configured properly, and it is used by "git diff",
but "git show" does not call the script and only returns unified diffs.

Is there a way to make "git show" use an external diff script?

-- 
  Bruce Momjian  [off-list ref]        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +