Christian Chavez -- the telenovela star who was also in a famous band -- got in a fight with his ex-boyfriend that led to their arrest over a tweet allegedly showing Christian dressed up like a woman.
Sources connected with the case tell TMZ ... Christian's ex -- Ben -- told Beverly Hills cops they both went nuclear early Tuesday morning after Christian confronted Ben about posting a picture on Twitter allegedly showing Christian in drag in West Hollywood.
We're told Ben informed cops Christian was upset because he thinks the pic would be damaging to his career.
As for what happened in Ben's apartment Tuesday morning ... Ben told cops the two had broken up a month before ... Christian was still staying in the apartment and planned on moving out permanently on Tuesday.
Ben said he woke up to find Christian videotaping him as he slept, which enraged him. Ben said he took Christian's cell phone and threw it against the wall, breaking it. Ben told cops Christian then retaliated by trying to take Ben's phone and damaging it.
The two started wrestling and punching -- each attempting to get the phone.
Ben told cops he tried to disengage by walking out of the apartment and Christian hit him in the back of the head and allegedly escalated things with some threatening actions. Ben claims he then locked himself in the bathroom and called 911.
Both men were arrested for domestic violence. And we're told this isn't the first incident where cops were called to the apartment. We're told in February police came after Ben claimed Christian threw a cinder block through a skylight (see photos above).