The music mogul Diddy has been arrested in the city of Los Angeles.

Yes, the ‘Hello Good Morning’ has faced the heavy hand of the law before the release of his brand new album.

Why?

Bad news below…

Read TMZ’s timeline of events from the bottom up:

6:50 PM PT — Diddy was cuffed in the back of a campus patrol car as officers transferred him to L.A. County jail.

4:35 PM PT — Sources connected with Diddy tells us the rap mogul is adamant he acted in SELF DEFENSE and was not the aggressor.

Our Diddy sources tell us … Diddy insists the drama began during a workout session yesterday because strength and conditioning coach Sal Alosi was “riding Justin badly” and told him not to come back until the end of the summer.

Diddy went to the campus today to speak with Alosi — believing he has an “issue” with Justin — but things didn’t go well when he arrived to campus.

Our Diddy sources say the coach would not see him and staff told him to leave … but Diddy went to Alosi’s office instead where Alosi told him to get out and threatened to call security if he didn’t leave.

We’re told Diddy said, “Fine, I’ll call police” … and Alosi snapped — going after Diddy with his hands.

We’re told Diddy insists he grabbed a kettlebell and held it up in a defensive position … but did not attack with an intent to injure the coach.

4:15 PM PT — Our UCLA sources tell us Diddy confronted Strength and Conditioning Coach Sal Alosi while Alosi was on the phone. We’re told Diddy was told to “hang on” but he wasn’t having it and picked up a kettlebell and swung it, narrowly missing Alosi. One source said if Diddy had connected, it could have killed Alosi.

Your thoughts?