He was charged with a felony assault with a deadly weapon, reported Ace Showbiz.
UCLA said in a statement, "Shortly after 12:30 PM, Sean Combs (also known as P Diddy) was arrested at UCLA's Acosta Athletic Training Complex on a charge of assault with a deadly weapon, which was a kettlebell.
"No one was seriously injured and UCPD is investigating. Combs is expected to be transported to the Los Angeles County Sheriff's Department Inmate Reception Center later this evening."
Diddy, 45, claimed he then grabbed a kettlebell and held it up in a defensive position but he did not intentionally attack the coach.