Perry: I was lonely during 'Friends'

Matthew Perry says he was "very lonely" when he was starring in 'Friends'.

The 43-year-old actor, who battled addictions to alcohol, Vicodin, methadone and amphetamines during his 10-year stint on the hit sitcom, admits he tried to hide his problems from the rest of the cast, including Jennifer Aniston and Courteney Cox, despite often being "painfully hung over" while filming the show.