Watch Will Ferrell and John C. Reilly Gleefully Reunite, Sing “Reunited” on Kimmel

Some friendships are just fun to watch on screen—like that of Stephen Colbert and Jon Stewart, or Jim Carrey and Jeff Daniels. Or Will Ferrell and John C. Reilly, who took to the stage of Jimmy Kimmel Live! Wednesday to remind us just how amusing it is to watch them do . . . basically anything, from singing a duet to talking about defecation.

Ferrell and Reillys fourth film together, Holmes & Watson, debuts this month. Their on-screen collaborations first began in 2006 with Talladega Nights: The Ballad of Ricky Bobby, followed by Step Brothers two years later; Reilly also appeared briefly in 2013s Anchorman 2. And although late-night stops are a standard part of the publicity tour, Ferrell and Reillys affection for one another is clearly genuine.

Both men were energetic as ever upon arrival, jumping up and down before taking their seats to discuss making the film—which involved shooting for three and a half months in England, during which time Reilly said he lived in a house boat on the River Thames. When Jimmy Kimmel asked them how they decided who would take which role, Ferrell joked, “At first we couldnt, so wed shoot every other day switching parts. . . . It was not cost-productive.”

The two discussed getting used to life in England—which, for Reilly, involved realizing he cant really handle the energy spike from drinking so much tea. The real highlight of the twos chat, however, came when Ferrell revealed a certain scatological euphemism Reilly loves to use: “When John has to go No. 2, which, youve heard the term drop a deuce,” Ferrell said, “he just says, Guess what, I gotta find my passport, because Im taking a trip to Düsseldorf. On a film set that just gets shortened to, You got my passport?”

If poop jokes arent your thing, there was also another highlight during Wednesdays appearance: before they left, Ferrell and Reilly went ahead and sang a duet. Naturally, it was Peaches & Herbs “Reunited.”

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Get Vanity Fairs HWD NewsletterSign up for essential industry and award news from Hollywood.Laura BradleyLaura Bradley is a Hollywood writer for VanityFair.com.