Reunited - and it feels so good.
The tag-team duo worked together on "Late Night with Conan O'Brien" for seven years.
Richter will participate in both taped and on-air segments as part of the show, but will not be onstage nightly with O'Brien like he was on "Late Night."
Host O'Brien said he's ecstatic to get back to work with his former sidekick.
"Andy is one of the funniest people I know, and we've maintained a close friendshpi since he left 'Late Night,' We have a proven chemistry that will be an incredible asset to 'The Tonight Show,'" he said.
Another reason he's anticipating Richter's comeback?
"He owes me $300," O'Brien joked.
Richter left O'Brien's show in 2000 to pursue a full-time acting career, starring in films like "Elf" and "Andy Richter Controls the Universe."
The comedian was the last guest on O'Brien's "Late Night" show before its lights were dimmed last week.