What happens in Vegas doesn't always stay in Vegas.
A source told E! News that Ashton Kutcher was in Sin City over the weekend for his producer pal Luke Watson's 40th birthday with, appropriately enough, 40 friends.
We also learned that, on Friday night, the group all ate at STACK in a private dining room, where they watched the Los Angeles Clippers take on Oklahoma City Thunder during Game 3 of the NBA playoffs.
Our source added that during the day on Saturday, Kutcher and company hung out at LIQUID Pool Lounge at ARIA, before hitting up HAZE Nightclub at ARIA later that night.
It's believed that the 36-year-old actor's pregnant fiancée Mila Kunis was not in Vegas with him.
Nevertheless, the pretty pair reunited for Mother's Day on Sunday to go to the Dodgers game together in Los Angeles.
Kunis' blossoming baby bump was on full display under a blue sweater from Peace Love World that read "I love Sundays" across the front. She paired the top with khaki pants.
Kutcher was equally as casual, decked out in a matching blue sweat jacket, white T-shirt, grey pants and a Dodgers' baseball cap.
"Sometime this year. I promise you," she teased. "It will be this year."
—Reporting by Baker Machado