DaveWatch: Countdown to Letterman's Last 'Late Show,' Day 10

Tina Fey strips down and an old Simon and Garfunkel favorite gets the cover-version treatment as the clock ticks down

Tina Fey strips down to her customized 'Bye Dave' underwear on 'Late Show With David Letterman.'

Remember those last few days of high school before summer vacation, where your finals were over and all you had to do was show up to class and enjoy hanging out with your friends? That's pretty much the same vibe David Letterman was radiating last night on the Late Show. Relaxed, affable, and seemingly on the perpetual verge of whistling a happy melody, Dave remained blissfully unfazed during the first half of the episode.

His Tom Brady/Aaron Hernandez joke elicited groans; he completely lost track of where he was in the middle of reading a cue card; and a congratulatory retirement message from Osama Bin Laden in the fiery pits of Hell zigzagged unsteadily between edginess and cringe-worthiness. None of that mattered. Nothing could pierce Dave's veil of serenity. The Number Two spot on evening's Top 10 list — "10 Surprising Facts About Sesame Street" — pretty much said it all: "Oscar the Grouch slightly nicer since announcing May 20th retirement."

Dave continued smiling during Tina Fey's guest appearance, but his genial mask of composure proved no match for Fey's sassy humor assault. The 30 Rock goddess had him practically coughing up a lung with her tart characterization of the recent Met Gala as a "jerk parade," and her tale of being crop-dusted by the "toxic fart cloud” of a famous man on the event's red carpet. "You're going next year," she predicted. "And you're going to wear a red leather dress!"

But it was Fey's form-fitting blue dress that elicited the biggest reaction from Dave and audience alike. Making her 20th appearance on the show since 2001 — "Because I live close by, and people cancel a lot" — Fey explained that this would be the last time anyone would see her wearing a dress on late night television. "What, am I going to put a dress on for Jimmy?” she said, referring to the Tonight Show's Jimmy Fallon. "That's creepy — he's like my brother!” She likewise negated the notion that she would ever don "special underwear” for the likes of James Corden. "That's not going to happen,” she said.

"Because this is my last time wearing a fancy dress on a talk show and conforming to gender norms, out of respect to you," Fey told Letterman, "my gift to you is, I want to give you the dress. You can keep it." But she had another gift in store for him, as well: After dutifully unzipping the back of the dress, Dave seemed completely gobsmacked when Fey stripped down to reveal a full Spanx ensemble with "Bye Dave” on the tummy and "#LastDressEver” on the tush. "Oh, my goodness!” was about the most coherent thing he uttered in response, at least until he managed to catch his breath. "I'm told now that we have time for another segment," he joked.

After Fey's bawdy farewell, First Aid Kit's enchanting version of Simon & Garfunkel's "America" — one of the songs Dave used to sing to his son Harry during "his early days on the planet" — seemed to help him regain his sense of comic equilibrium. "Thank you, that means a great deal to me,” he told the musicians. "We can't pay the strings," he added.