Matt Damon and David Letterman surprised viewers during Sunday night’s Season 4 premiere of “The Gilded Age” with a brief, wordless appearance as gentlemen crossing the street.

The cameo took place more than eight minutes into the episode, as the camera moved past the pair toward George Russell’s home. Russell, played by Morgan Spector, was recovering after being shot at the end of Season 3.

Damon appeared with faux sideburns and a mustache, wearing a top hat, white shirt, long black coat and slacks. Letterman wore a bowler hat, a black coat and slacks, with his white beard visible.

The uncredited appearance quickly drew attention on social media. According to Vulture, it was connected to Letterman’s nearly 50-year effort to work as a background actor. His “My Next Guest Needs No Introduction” team had been researching Damon, who began his career as a background actor alongside Ben Affleck, for a potential episode.

Showrunner Isabel Richardson said the team saw an opportunity to pair Letterman with Damon while connecting the appearance to Damon’s early career. The idea was then presented to the “The Gilded Age” production, eventually reaching executive producer Kate Churchill, creator and showrunner Julian Fellowes, HBO head of drama Francesca Orsi and HBO CEO Casey Bloys.

Churchill said the collaboration involved complicated arrangements, including paying Damon as a background performer while he worked through his own company. She added that both studios supported the idea as a fun collaboration.

Neither Damon nor Letterman received credit for the roles. New episodes of “The Gilded Age” air Sunday nights at 9 p.m. ET/PT on HBO.

Sources: Page Six.