Jimmy Fallon did not hurt any of his body parts last night, but he did have to take a time out during the monologue section of "The Tonight Show" for a "sickness." Billy Crystal was on set at the show and took over joke telling duties from the host.

During a run of jokes about the ages of the Democratic presidential candidate frontrunners, Bernie Sanders and Hillary Clinton, Fallon led the audience in some "how old is he" humor. Mid-way through the jokes, Fallon announced to the audience that he had "a little tickle" in his throat and "needed a lozenge." Out walked Billy Crystal to tag in for the host.

"Boy, that Bernie Sanders sure is old," Crystal joked. "He's so old, he thinks a trickle-down theory is about him urinating."

"Hillary is so old when she hears 2016, she yells bingo!" Crystal said of Clinton. "She is so old her first political scandal was deleting all of her telegraph messages."

"She is so old she remembers when Jimmy Fallon had hands," Crystal said as Fallon walked out on stage to "tag back in."

The two then traded off on more "how old is he" jokes at the expense of Clinton and Sanders.

This is not the first time Fallon let a legendary comic sub in for him during "The Tonight Show" monologue. Jay Leno, the former host of the show, returned last month to his old stomping grounds and took shots at multiple political leaders like Clinton, Sanders, Marco Rubio, Jeb Bush and of course, Donald Trump.

Check out Fallon and Crystal's monologue below.