After David Letterman's last show yesterday, Drew Barrymore is reminiscing about that time she was on the show and flashed the talk show host on live television.

It was a birthday gift in 1995 that left Letterman very, very thankful.

Barrymore was a guest on the "Late Show With David Letterman" on Letterman's 48th birthday so she danced for him, which led to her getting on his desk and flashing him.

"He's always been known as the person who had no problem letting the audience know he was not down with what the guest was doing," Barrymore told Entertainment Weekly. "It was scary."

She told EW that the dance 20-years-ago was "completely spontaneous."

Although it definitely caught Letterman off guard, Barrymore's risque decision got her a lot of cheers and a big thank you from Letterman.

"I can't thank you enough for that," Letterman said as soon as she finished her dance.

Watch the clip here: