The Hollywood star, who is Julia Roberts' brother and the father of teen actress Emma Roberts, recently joined the cast of the new season of Celebrity Rehab, where Pinsky attempts to help his high-profile patients battle their drug and alcohol demons once and for all.
Details of Roberts' addiction problem were never fully disclosed, although his publicist Chuck Jones told WENN, "It's not for anything serious. He's not hooked on prescription meds or hard drugs or anything like that."
Roberts has now revealed he is receiving treatment for his pot habit - and the rehab programme is going so well, it allowed him to walk the red carpet sober for the first time ever at the Los Angeles premiere of his action movie The Expendables on Tuesday (03Aug10).
He told Eonline.com, "I have never walked down a red carpet without being stoned in my life until tonight."
Roberts, who was arrested in 1987 for cocaine and marijuana possession, continued to battle a cocaine problem throughout the 1990s. He joins fallen pop star Leif Garrett and fellow actor Jeremy London on the new season of Celebrity Rehab, which began shooting last month (Jul10).