The two will meet for the 185-pound crown in the second half of 2017, according to the UFC.
And they can happen for much higher stakes if St-Pierre does beat Bisping and join McGregor, Randy Couture, and BJ Penn as one of MMA's few heralded multi-division champions in the UFC.
It's a remarkable scenario, as St-Pierre is perhaps the greatest welterweight in UFC history and defended his 175-pound title nine consecutive times before his departure, whereas Bisping had to wait a decade for his chance to become champion.
That means he'll be returning to the Octagon with his 12-fight winning streak still intact, but this will be his first time competing at middleweight, where Bisping now rules the roost.
The bout will be for Bisping's UFC Middleweight title.
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Toronto are now fourth in the Eastern Conference standings and on course to reach the playoffs with a 35-24 record. DeRozan's now fifth in the National Basketball Association in scoring this season, averaging 27.7 points per game.
This Friday prior to the UFC 209 weigh-ins, the organization will host a Bisping vs. St-Pierre press conference to formally kick things off.
But those contractual issues were eventually resolved, leading to St-Pierre officially re-signing with the UFC last month. Even Muhammad Ali, after a long layoff, didn't look the same. They think he's beatable and obviously, Georges St-Pierre is no different. "That's the only reason he's in my mind", Bisping said recently on The MMA Hour. He has long said, however, that he would not pass on the option to fight St-Pierre if it were offered. If "GSP" wins as many are expecting him to, then he probably won't face Romero or Souza in his first title defense. I want it for my family's sake. That's what he wants, that's what he'll get.
St-Pierre admitted last year that he was anxious he would regret, years down the line, not coming back, especially because he felt "right now that I'm at my best ..."
Bisping will now get his wish, and one of the Octagon's most fabled names will once again be returning to the eight-sided cage.