Sen. John McCainJohn Sidney McCainTrump's plan to claw back spending hits wall in Congress Defense bill moves forward with lawmakers thinking about McCain How House Republicans scrambled the Russia probe MORE (R-Ariz.) took to Twitter on Thursday to endorse "Tonight Show" host Conan O'Brien as a funnyman.

Conan took over the reins as "Tonight Show" host from Jay Leno in June, so we're sure the former "Late Night" host is pleased with such a high-profile endorsement.

The 2008 presidential nominee appeared on the show Wednesday night and discussed a variety of topics, including his ex-running mate Sarah Palin's (R) abrupt resignation from the Alaska governorship.

McCain tweeted:

Back in Arizona. Had a great time on the Tonight Show last night - Conan is a funny guy!!

When asked if he was shocked about Palin's resignation, McCain said "Yeah, I was because she didn't call me ahead of time," garnering laughter from the audience.

"We all have families, we all have challenges, we all have issues in our lives. She did have huge legal debts because of these [ethics] charges," he added.