Justin Bieber turned ALL THE WAY UP with a Division 1 football player this weekend -- a defensive back at UCLA -- who also happens to be the heir to the Bad Boy empire.
Bieber rolled up to a mansion in Bel Air on Saturday night ... for Justin Combs' 21st birthday party -- a '90s-themed shindig MC'd Branden King that featured appearances by a ton of stars including Khloe Kardashian, Kendall Jenner, Mase, French Montana and, of course, Diddy himself.
Combs is a redshirt sophomore for the Bruins ... though he only had one tackle in the 4 games he played in during the 2014 season.
It's possible Diddy's kid could play on the same team as Snoop's son next season -- UCLA has been recruiting Cordell Broadus -- though C.B. is reportedly still weighing his options.