The Wedding Ringer star also shared this snap of the two posing in front of a giant grizzly bear in matching orange sweaters and white pants.
"2 questions...Question #1, Why are we sitting this comfortably in front of this grizzly bear? Question #2, Why are we dressed alike? Gotta love @davidbeckham #Twins #GoodTimesWithGreatPeople," Kevin wrote.
Meanwhile, David also joked, "I can't seem to shake this guy off! @kevinhart4real #lovethisman #twins.”
But it turns out, the two are even workout buddies.
Well whatever Kevin's doing, clearly, it's working. Check him out showing off his rock-hard abs in an elevator.
Kevin actually turned 36 on Monday, and the hilarious actor spent it working ... which he admitted he wouldn't have any other way.
"Celebrating my B Day by doing what I love....WORKING...I'm headed back to Boston....Can't wait to get on set in the a.m.," Kevin Instagrammed on Sunday. "I'm blessed to see another year of life while having the people that I love the most around me!!!! I'm officially the big 36 people!!! #HappyBDayToMe."