CM Punk's debut in the Octagon is rapidly approaching and if his sparring sessions are any indication, his wife AJ Lee will be on an emotional roller coaster during the fight.

The former WWE Champion is set to battle Mickey Gall at UFC 203 at the Quicken Loans Arena in Cleveland on Sept. 10. After signing with the MMA promotion in December 2014 and suffering many set-backs, this will mark Punk's first fight in the Octagon.

A clip from Episode 2 of the "Evolution of Punk" documentary, a four-part series which chronicles the former wrestler's journey to his debut, shows Lee sitting cageside and watching the "Best in the World" spar with more experienced competitors.

The clip shows Punk, 12 weeks into his training, sparring with others in front of a nervous Lee, who at one point says, "I can't handle this."

Though Punk was dominated by his opponents, he says later on in the video that he expected this to happen.

"I'm sparring with guys that should absolutely beat me every single time," Punk says in the clip, "but that's when you learn. You fall flat on your face, you get up."

Lee then describes the horror she felt while watching her husband spar.

"Oh my god, I think my nails went all the way through my arm," Lee says in the clip. "I don't think I breathed out once that entire time. You can see how happy he is when he gets out of [the cage]."

It will only get harder for Lee to watch come Sept. 10 when Punk enters the cage behind a lot of buildup to matchup against Gall, 24, who has a deeper mixed martial arts background and is undefeated in UFC at 2-0.

Punk walked out on the WWE back in January 2014 and after signing with the UFC that December, he has been preparing for his first fight. He had many setbacks in his journey, which most recently involves back surgery.

Lee, whom Punk met in the WWE, retired from Vince McMahon's company in March 2015, over a year after her husband walked out.

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