Reggie Watts Loses Festival Gigs After Exes Accuse Him of Reckless Drug Behavior

Reggie Watts -- the comedian and musician known for his work on "Comedy Bang! Bang!" and "The Late Late Show with James Corden" -- is suddenly disappearing from festival posters ... after explosive claims about drug use and alleged abuse surfaced.

Rolling Stone reported last week that loved ones of Watts' late ex-girlfriend Katherine McCollough -- along with several women who previously dated him -- accused him of reckless drug behavior and crossing boundaries in relationships.

And now, gigs are vanishing.

Watts has been removed from the lineups for the Shambala and Greenbelt festivals in England this week ... while a run of Bristol shows with collaborator CAPYAC were also canceled.

Greenbelt confirmed to Rolling Stone that Watts is no longer appearing ... and Shambala scrubbed his name from its site.

The fallout has also reached "Comedy Bang! Bang!" ... which quietly dropped the theme song Watts created for the show.

Rolling Stone says McCollough's loved ones believe Watts encouraged her drug use during their relationship ... she died by suicide in March after they separated last October.

Watts' attorney called any suggestion he was responsible for her death "dangerously false" ... and disputed claims he pushed her into drug use. Watts has also denied being an abusive boyfriend.

For now, his festival calendar is getting a lot lighter.