In a preview of an interview set to air Monday afternoon, CBS Late Show host Stephen Colbert called Republican presidential nominee Donald Trump a “chicken” because the former reality TV star won’t make a return appearance on his show.

The Wrap reported that Colbert made the remarks during an interview with Sirius XM’s Bill Carter that will air at 6:00 p.m. Eastern time on Monday.

Carter, a former New York Times reporter, asked Colbert if he thinks that Trump will make a follow-up visit to the Late Show after his interview with Colbert in September of 2015.

Colbert replied that he doesn’t think Trump will come back because “he’s a chicken.”

“I regret that that’s probably the only bite I’m going to get at that apple,” Colbert told Carter. “I would have him on tomorrow, but he’s a coward.”

The former Comedy Central host said he’s in touch with Trump campaign personnel, but “it is clear that Donald Trump is a coward because he won’t come back on the show.”

He then made clucking sounds like a chicken.

The broadcast will air on Sirius XM’s Insight Channel, No. 121.