Donald Trump called in to the "Late Show with Stephen Colbert" Tuesday night, and jokingly agreed to start a swear jar that he'd put $1 billion into every time he uses a bad word.

Colbert said he doubted Trump could stop using his "potty mouth" during the campaign, and interviewed Trump over the phone.

"How are you going to stop?" Colbert asked Trump about his foul mouth.

"Well, it's easy, I've decided to stop," Trump said. "I mean, I do that for emphasis, and I do that sometimes non-politically."

"These are very minor words, and in many cases I actually bleep them out myself, I never said the word, and then they'll bleep it and people will think I said the word," he added.

"I've got a suggestion," Colbert said. "Why don't you have a swear jar, every time you say a bad word, you put a billion dollars in it?"

"Well, I think that's a good idea," Trump said. "I'm gonna do that, I like that."