For some of Capitol Hill's heavy hitters, it's lights, camera, cameo.

Actors from the NBC show "Parks and Recreation" traded their fictional town of Pawnee, Ind., for Washington, D.C., last week to film an episode for the show's upcoming fifth season, including a stop on Capitol Hill to appear with some of Congress's long-standing senators.

And there's a spoiler alert from inside the Beltway: The show's headline actress, former "Saturday Night Live" funny girl Amy Poehler and her co-stars aren't the only ones getting ready for their close-ups.

Sens. John McCain, R-Ariz., Barbara Boxer, D-Calif., and Olympia Snowe, R- Maine, will also guest star in an episode that airs this fall. They'll all play themselves in cameo roles.

"Had a great time shooting @ ParksandRecNBC today w/ Amy Poehler - I think it's an Emmy!" tweeted McCain last Thursday during the filming. He also tweeted a photo of himself alongside Poehler, who earned an Emmy nomination last week for her portrayal of a small-town bureaucrat on the show.

The two first met while taping one of McCain's many "Saturday Night Live" appearances. Notably, while a Republican presidential hopeful in 2008, McCain stopped by the show to do a political ad parody, give his 2 cents as a guest on "Weekend Update" and star as himself opposite Tina Fey's infamous Sarah Palin.

Snowe also took to the Twittersphere last week to plug her upcoming TV appearance, tweeting, "I enjoyed speaking with @ SenatorBoxer and the hilarious Amy Poehler after shooting a scene for @ ParksandRecNBC today." She also tweeted a picture of the trio.

The upcoming "Parks and Recreation" episode follows newly elected city councilwoman Leslie Knope (Poehler) as she heads to the nation's capital to visit her boyfriend, congressional staffer Ben Wyatt, who is played by Adam Scott.

Wyatt invites Knope to a cocktail party attended by "several high-powered politicians," where the two hobnob with Boxer, McCain and Snowe, according to NBC.

The episode is slated to air Sept. 27, at 9:30 p.m. on NBC.