The Tyra Banks Show featured a couple of undercover investigations with Tyra disguised with prosthetic makeup. The first of these in 2005 garnered the most publicity when she went undercover as a seriously overweight woman. She also went undercover as a stripper.
Serious investigative reporting this is not but it was done with serious intent and not played for laughs.
She has also done a Halloween makeup – a fakeover of Paris Hilton.
I believe that Todd Tucker (now of Illusion Industries) was responsible for these makeups.