(Cover) - EN Showbiz - Casey Affleck says shooting his new Joaquin Phoenix documentary was completely draining.

The actor makes his directorial debut in Im Still Here, a bizarre film about Joaquins decision to quit acting and start a career as a rapper. The documentary premiered at the Toronto International Film Festival on Friday, and features scenes of drug use, wild partying and strange sex acts.

Casey followed Joaquin for two years shooting the movie and says the project left him totally exhausted.

Making this was satisfying creatively, but exhausting in all other ways. By the end, I was just completely drained, Casey told USA Today newspaper. Not only by the experience, but also the experience of putting it together.

I got through a whole other journey and had my own difficulties. I was pretty new to it. I had done commercials and short films, but I had something like 400 hours of footage and I watched every minute.

Casey and Joaquin have been friends since they were teenagers. Casey is married to Joaquins sister Summer Phoenix and insists he and Joaquin are closer than ever after making Im Still Here.

An experience like this was incredibly difficult, but it is a drop in bucket next to 20 years of friendship, Casey explained. He's my brother-in-law. If we had been strangers, it probably would have transformed our relationship and lives. But we have stayed very close. (C) Cover Media