Sonnen revealed the fight Tuesday night on Fuel TV. UFC has not officially announced the fight or where it will be held.
"I've watched him win the (205-pound) world championship," Sonnen said. "I've watched him etch his name in stone as a guaranteed future hall of famer.
"He's the one guy Jon Jones hasn't fought. He's beaten two world champions in his last three outings and on Dec. 29 I will be taking on Forrest Griffin.
"That fight will be at light heavyweight, absolutely."
Griffin is no stranger to Sonnen. The two met in a light heavyweight bout on Sept. 6, 2003. Griffin submitted Sonnen in the first round.
"A number of years ago I fought with (Griffin) who turned out to become a very good friend of mine; I lost the match," Sonnen said. "Since becoming friends and competitors with him I've also become a fan."
The rematch with Griffin will be Sonnen's first since his second-round TKO loss to Anderson Silva on July 7. It will also be Sonnen's first fight at 205 pounds since October 2005.
Sonnen (27-12-1) hopes a victory over Griffin will springboard him into a title bout against Jones, the current UFC light heavyweight champion.
"Sure, I can go up to 205 and take Jon Jones' belt away the same as I can take his candy on Halloween; the little punk kid, I can snatch it all I want," Sonnen said. "But there is something to be said in sportsmanship in earning your shot.
"And on the 29th of December I'm going to go through Forrest to do it."
Griffin, who held the UFC light heavyweight title briefly in 2008, defeated Tito Ortiz by unanimous decision on July 7.
Griffin has a professional mixed martial arts record of 19-7.