It appears that alcohol may be to blame for Green Day frontman Billie Joe Armstrong ’s profanity-filled tirade at last weekend's iHeart Radio music festival in Las Vegas.

Claudia Suarez Wright , the ex-wife of drummer Tré Cool , says that Armstrong -- who'd been sober for about a year -- had reportedly been drinking heavily during his time in Sin City.

“When he was in Vegas he was drinking a lot,” Suarez tells Celebuzz . “The night of the show he had been drinking. In Las Vegas there's a lot of temptation to drink and it's tough to be around when you're fighting against it. They have a new album coming out and it's a demanding lifestyle. It's very difficult."

The day after the Las Vegas incident, Armstrong apologized for his behavior and announced that he would to be heading to rehab to seek treatment for substance abuse.

Copyright 2012 ABC News Radio