Green Day lead singer, Billie Joe Armstrong, freaked out at the iHeart Radio Music Festival on Friday night, September 21,  and has now entered rehab for substance abuse according to TMZ.com.

Armstrong became belligerent after he was given a one-minute warning during Green Day's set.  He dropped the "f-bomb" numerous times (the reason I won't post the video, just in case you accidentally open it at work) and he smashed his guitar.

If you really want to see the video, you can go to You Tube and search Billie Joe Armstrong iHeart Radio Music Festival.