Drew Barrymore flashes David Letterman for his birthday
In 1995, Drew Barrymore was struggling to cope with fame, acting out in a number of ways—one of which happened right on the set of The Late Show. Letterman invited Barrymore on the program for an episode that would take place on his birthday.
Barrymore had a special "gift" she had planned for Letterman, which involved flashing him on-air. Letterman was shocked, and it made for some fantastic television. 26 years later, Letterman returned the favor (well, sort of) by surprising Barrymore on her own series, The Drew Barrymore Show. The gesture brought her to tears.