Cameo
/ˈkæm.iː.əʊ/
noun
A piece of jewelry, etc., carved in relief.
A single very brief appearance, especially by a prominent celebrity in a movie or song.
“Famous comic book writer Stan Lee had a cameo in the Spider-Man movie. He was on screen for perhaps ten seconds, but aficionados distinctly remember him.”
verb
To appear in a cameo role.