UFC officials announced the bout on Sunday.
Diaz and Maynard first met in the semifinal round on the fifth season of The Ultimate Fighter. Diaz submitted Maynard with a guillotine choke. That bout doesn’t appear on the fighters’ official records due to it being a part of the reality series.
They met again in the main event of UFC Fight Night 20 on Jan. 11, 2010. Maynard won that night via a split decision.
Diaz (16-9) is currently on a two-fight skid, having lost back-to-back bouts to Benson Henderson and Josh Thomson, and in desperate need of a win.
Maynard (11-2-1), after twice failing to wrest the UFC lightweight belt from then-champion Frankie Edgar, is 1-1 in his last two bouts. He won a split decision over Clay Guida before losing his most recent fight to TJ Grant.
The TUF 18 Finale takes place on Nov. 30 at the Mandalay Bay Events Center in Las Vegas.