Watch: Look Back at Regis Philbin Dropping in on David Letterman in a Full 'Shrek' Costume

When news surfaced about Regis Philbin's death at the age of 88, fans and peers alike mourned the [...]

When news surfaced about Regis Philbin's death at the age of 88, fans and peers alike mourned the loss of a TV icon. Several also revisited memorable moments from his career, including the time he dressed up as Shrek. Philbin did so solely for the purpose of making former late-night host David Letterman laugh.

The moment took place during a 2009 appearance on the late-night show. Philbin was hosting Live! With Regis and Kelly while Letterman was still at the peak of his longtime career. Fans questioned at the time why Philbin dressed up as Shrek, but Shrek The Musical was in the middle of its run on Broadway. Philbin embraced the joke and underwent a long transformation.

"Guess who I am?" Philbin asked as he walked toward Letterman's desk. "Guess who I am? [...] It's not Regis! It's Shrek! Biggest mistake I've ever made. 2.5 hours across the street, putting this stuff on. Another two hours sitting in the green room while you're staring at Beyonce's earrings."

While Philbin had a hope of bringing entertainment to his longtime friend, Letterman reacted in a very different manner. He asked if Philbin wanted to go visit with some "ladies of the night." This question caught the TV host by surprise, but he responded by saying that "Regis would probably say no, but Shrek is ready."

Philbin only remained on the show for a little over two minutes, but he brought entertainment to several viewers at the time. There were many that reminisced about this moment on social media while paying tribute to the late TV icon. Although a few simply noticed something unique about the entire interaction with Letterman.

"my favorite thing about this is that he's not trying to make a shrek voice or anything. he's just regis and he happens to be wearing a full shrek costume," one person commented on social media. Another responded by proclaiming that Regis was likely "done with the bit" hours prior to his appearance on Letterman's show.

This moment drew considerable attention at the time, but fans revisiting it used the moment as the perfect example of the friendship that lasted several decades. Even if they didn't agree with some of the jokes, these Twitter users still took a few moments to enjoy Shrek Philbin's appearance on Letterman's show.