Viewers might have thought it was just a gag when Stephen Colbert rolled out the "Trump Phone" — an orange phone adorned with a wig that rang by just yelling the name "Trump" — on CBS' "The Late Show with Stephen Colbert" Tuesday night. But then — surprise! -- the Republican presidential front-runner actually did call in. 

Colbert and Donald Trump arranged a "Late Show" first as the controversial candidate called in for the sort of phone interview that is much more common on cable news programs. Trump was calling from South Carolina, Colbert's home state, where he is campaigning for the state's Republican primary, to take place Saturday. 

Colbert kicked things off with a tough question: "What are you wearing?" Apparently, Trump was wearing a blue suit and "a very poor tie."

Eventually, the pair got into a discussion about the South Carolina primary. Colbert questioned if Trump could curb his penchant for foul language on the campaign trail to preserve his appeal to Southern voters.

"I can think off of the top of my head, three things that you have said that CBS will not let me repeat or it would have to bleep them," said Colbert. "How are you going to stop?"

Trump told the host it would not be a problem.

"It's easy. I've decided to stop. I do that for emphasis and sometimes nonpolitically, and once I decided to run for office I said, 'Well, we are going to have to stop,'" said Trump.

When Colbert countered that Trump had not, in fact, stopped, Trump insisted that his recent controversies were just "minor words" that the media exaggerated into bigger stories. 

In any case, Colbert had a solution. 

"Why don't you get a swear jar, and every time you say a bad word you have to put in a billion dollars," suggested the comedian. 

Watch Donald Trump call into "The Late Show with Stephen Colbert" below:

Toward the end of the segment, which was planned in advance and promoted by Trump on Twitter, Colbert asked about the emerging political battle over replacing Supreme Court Justice Antonin Scalia. Trump told Colbert that President Barack Obama had a right to nominate a replacement and that he would do so were he in the same position, but Trump added that the Senate had a "daunting right" not to hold a confirmation hearing until a new president takes office in 2017. The issue has suddenly been injected into the presidential primaries. 

The South Carolina Republican primary is Saturday. Trump holds a commanding lead over the rest of the field in the latest polls