Ben Affleck snuck a surprise guest onto the Jimmy Kimmel Live show.

The Batman v Superman: Dawn of Justice star arrived on the late night show to be interviewed by Kimmel looking a little larger than usual.

Waddling onto the set in a giant buttoned-up coat, Affleck explained that "when you do a super hero movie, you get muscle, and muscle turns to fat".

Kimmel remarked that Affleck had "really ballooned up" then unbuttoned the coat to reveal that actor Matt Damon was hidden underneath, strapped to Affleck.


Kimmel wasn't happy about Damon's arrival, saying "you're ruining the Oscar's show, no one wants you here".

Damon was up for Best Actor for his role in the movie The Martian, but lost out to Leonardo DiCaprio at yesterday's ceremony.

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Kimmel then tried to have Damon cut out of the camera shot, before the actor was eventually dragged off by security.

It seems the host still hasn't gotten over the "F*@#ing Matt Damon" music video the actor made with Kimmel's former girlfriend, comedian Sarah Silverman.

Affleck and Damon have been life-long friends, winning Oscars in 1997 for their work together on the film Good Will Hunting.

Affleck was visiting the Jimmy Kimmel Show to promote Batman v Superman which is out in New Zealand on March 24.