The E! reality stars were spotted at The Commons in Calabasas, Calif., near the brunette beauty's new $20 million home in Hidden Hills, where they caught a screening of Teenage Mutant Ninja Turtles.
Kim was relatively dressed down in a pair of gray skinny jeans, a black bomber jacket and her signature pointy pumps.
She pulled her hair back and opted to wear little to no makeup on her playdate with the adorable toddler.
Meanwhile, Kourtney Kardashian's son looked as cute as can be in a T-shirt, matching gray shorts and a pair of high-top sneakers.
Earlier in the day, Mrs. West posted a picture on Instagram of several turtles crawling up a rock and wrote, "Teenage mutant ninja turtles time." So clearly, it wasn't only Mason who was super excited about catching the popular flick on the big screen.
Kim most recently returned home from a trip to Mexico with hubby Kanye West, where he's currently recording his highly anticipated next studio album.
The 33-year-old has been sharing several snapshots from her trip, including sexy bikini selfies, beautiful sunset views, and a romantic shot of her with her man. Sounds like a fun trip to us!
Watch an all new Keeping Up With the Kardashians Sunday night at 9 p.m.only on E!