The star has admitted that he dabbled in different "substances" in the past.  The now clean-cut singer opened up about his experiences in an interview with Myspace.  According to The Sun, Timberlake said "This is my first time here (speaking of the SXSW Festival).  I've been to Coachella many times, on many different, um, substances.  I've been to Coachella many times but not remembered it, I'll leave it at that.

The Sun