Spoiler alert! The following contains details from the Season 4 premiere of "The Gilded Age."
Season 4 of "The Gilded Age" had some rather golden celebrities make a cameo in the premiere episode, but you probably didn't notice.
David Letterman and Matt Damon made a quick six-second appearance in the Season 4 premiere of the HBO period drama about the haves and the have-nots in this historical period of American riches and excess. Walking across the show's main setting of 61st Street in New York City, the appropriately dapper Letterman and Damon show up in a blink-and-you'll-miss-it moment.
The former late night host and "Odyssey" actor don't have any lines in the brief cameo, which happens around eight minutes and 30 seconds into the episode. But
they did have extremely bushy facial hair (although it appears that while Damon needed help from the makeup department in that regard, Letterman's beard is already 1800s-ready).

So, why are they strolling across the muddy streets of historical New York in HBO's popular costume drama? It's all for Letterman's Netflix show, "My Next Guest Needs No Introduction."
In an interview with Vulture, "Next Guest" producer Isabel Richardson said the cameo originated in Damon and Letterman's conversation on the talk show, which will air in the upcoming seventh season. Damon talks about how he started out in Hollywood as a background actor (commonly called "extras") and Letterman, apparently, has always harbored a desire to try his hand at it.
"We thought, 'Okay, this could be the perfect opportunity,'" Richardson told Vulture, noting they were discussing a fun "field segment" that the pair could do as part of the episode. "It’d be really fun for Dave to do this with Academy Award-winner Matt Damon, and it tied into his origin story really well."

Damon was on board and "unequivocally chose this idea as his favorite. And this was by far the silliest, most ridiculous idea," Richardson said.
Through someone who knows someone, the idea eventually got pitched to "Gilded" executive producer Kate Churchill.
"It was a kind of hysterical moment when our production supervisor Leah Baker came up to me on set and was like, 'Well, I have a kind of funny, interesting question: Would you like Dave Letterman and Matt Damon to be background on our set one day?'" Churchill said to Vulture. "I just started laughing."
Churchill got the idea approved by "Gilded" creator Julian Fellowes, plus HBO head honchos Francesca Orsi and Casey Bloys, and they came up with a cameo specifically designed not to be distracting.
"There’s a very specific number of days that that could happen, and our schedule is set. I went back to Isabel like, 'These are your choices of days, and it has to work for both these guys,'" Churchill said. "I have to really give credit to our studios because a simple idea was actually quite complicated. Things like, Matt had to be paid as a background person, but of course he works under his own company. There were a lot of emails going around, but people really locked arms, and both studios saw that it was a fun collaboration where we could help each other."

Richardson also told Vulture that the Netflix show will include behind-the-scenes footage about what Letterman and Damon had to do to get ready for their background moment, from costuming to makeup and facial hair. Richardson said, "Matt Damon was laughing so hard throughout the day, and he had this mustache on, so anytime he laughed, he would have to hold on to his mustache to make sure it didn’t come loose."
"Next Guest" Season 7 doesn't have an announced premiere date yet, but in addition to his conversation with Damon, Letterman will also sit down with Julia Roberts, Jimmy Kimmel and Alex Honnold.
This article originally appeared on USA TODAY: Matt Damon and David Letterman are extras in 'Gilded Age' Season 4. Seriously!













