Donald Trump can consider the gauntlet thrown.

Stephen Colbert challenged the presidential candidate to appear on the Late Show when he takes over the CBS program later this summer.

"This is not an invitation, Mr. Trump. This is a dare," Colbert said during an interview with ETonline's Leanne Aguilera. "I dare you to come on the show."

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Trump will have to wait in line, though, if he's hoping to be on the show first. That spot already belongs to George Clooney, who will break in the new Late Show guest chair.

"What I like about George Clooney is the man has his own spy satellite," Colbert said. "He does Nespresso commercials in Europe to pay for a spy satellite to help protect the peoples of Sudan. C'mon, nobody else does that. Step up, Brad [Pitt]!"

In 2013, Clooney told The Guardianthat most of the money he makes from the Nespresso ads goes to "keeping a satellite over the border of North and South Sudan to keep an eye on Omar al-Bashir [the Sudanese dictator who was accused of war crimes]."

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Colbert officially takes the reins of Late Show on Sept. 8, but last week he was back in familiar digs for Jon Stewart's farewell episode of The Daily Show.

"I think it might be my favorite thing I ever did on that show," Colbert said of Stewart's Aug. 6 farewell. "All I ever really wanted to do was make Jon Stewart laugh on that show, but to make Jon Stewart cry a little bit ... I didn't realize that was going to be even more fun."