The late-night circuit has been a popular route for many GOP candidates for weeks. Below, we take a look at how they've performed.
Mitt Romney on Late Show With David Letterman
The No. 1 thing Mitt Romney would like say to the American people?
"It's a hairpiece," Romney said after counting down the Top Ten Things Mitt Romney Would Like to Say to the American People on "The Late Show with David Letterman" on Monday.
Watch clips of his appearance:
Play of the Day! 12/20/11
Rick Perry on Late Show With David Letterman
The Texas governor turned up on Letterman's "Top 10" segment in November -- to poke fun at himself the day after an embarassing debate gaffe.
Ron Paul on The Tonight Show With Jay Leno
On Jan. 16, Paul sat down for an extended, late-night interview where he told Jay Leno what he thinks of his GOP competition. (Watch the full interview at NBC.com.)