The Piranha 3-D star, who wed actress June Diane Raphael last October (10), commissioned a professional to take on the lead groomsman role and even penned the faux-Nicholson's speech so he'd amuse guests.
Scheer explains, "I couldn't figure out who to be my best man (sic)... You don't want to offend one of my friends and I don't have a brother, so, I was like, 'Who could it be?' And I was like, 'I should get a Jack Nicholson impersonator to be my best man.'
"He was amazing. And I wrote him this whole speech so he could come out and be like, 'Paul and June are As Good As It Gets. Being at this wedding, I can cross it off my Bucket List.'"
But Scheer admits, the plan ultimately backfired.
He added, "He couldn't remember any of the stuff. He'd be like, 'Can you put it on a teleprompter for me?' And I was like, 'I can't put it on a teleprompter, it's a wedding.' And he was like, 'Alright I'll try.'
"I think he had a couple beers because he started forgetting his Jack Nicholson lines, and he just started saying things like, 'Yummy, yummy'... But then he goes, 'Well guess what, I'll just stand over here and give everybody hugs.'"