Mason Dash Disick, Kourtney Kardashian and beau Scott Disick's 9-month-old, is on the move.
"Mason's crawling today!" Bruce Jenner told Usmagazine.com at Thursday's premiere party for Keeping Up with the Kardashians and The Spin Crowd at West Hollywood hotspot Trousdale.
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"It's big!" Jenner, 60, added of his step-grandson's milestone. (Married to Kris Jenner, the former Olympian is stepdad to Kourtney, Kim and Khloe Kardashian.)
"He kind of shuffles on the ground, but he actually got up to his knees today and started crawling," he explained of Mason.
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Added grandmother Kris Jenner to Us: the little boy is "becoming a little person!"
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"We take Mason with us everywhere," his mom Kourtney told Us at an event last week. Will he get a little brother or sister anytime soon? "Maybe down the road," Kardashian told Us. "I'm focused on Mason. I love being a mom. I never thought I would love it this much. It's better than I ever imagined."