Robin Williams fell off the wagon during his reluctant and ill-fated return to series TV when he insisted on downing real booze during a shoot at the famed Spago restaurant last year, The Post has learned.
The tragic funnyman appeared sober when he began taping “The Crazy Ones” for CBS and was “crazy manic” but manageable, a Hollywood insider said.
But when the cast went to shoot a scene in May 2013 that involved a business meeting at Wolfgang Puck’s iconic power-lunch spot in Beverly Hills, “Robin insisted on a real drink,” the source said.
“No one had seen him drinking before this,” the source said. “One drink led to another, but it seemed to calm him down.”
Williams, 63, admittedly got addicted to cocaine and alcohol after he shot to stardom with the smash-hit ’70s sitcom “Mork & Mindy,” on which he played a befuddled outer-space alien adapting to life in Boulder, Colo.
He quit cocaine and booze cold-turkey before the 1983 birth of his eldest child and was sober for two decades but went to rehab in 2006 after a drinking relapse.
The Oscar-winning actor also returned to rehab at the Hazelden residential treatment center shortly before his shocking suicide, in which he was found hanged with a belt after an apparent failed bid to slash his wrist with a penknife inside his California home Monday.
While taping “The Crazy Ones,” Williams frequently engaged in his trademark frenetic shtick, veering off script and forcing co-star Sarah Michelle Gellar to improvise her responses, the source said.
“No one had seen him drinking before this … One drink led to another, but it seemed to calm him down.”
His antics infuriated the cast, even though he had been hired to try recreating the madcap spirit of “Mork & Mindy,” on which he often riffed unscripted, the source said.
He also indulged himself by taking his pet pooch, a rescued Pug named Leonard, to work.
“He brought it everywhere with him,” the source said. “When he wasn’t filming a scene, he was holding and petting and fawning over the dog.”
Williams — who last year said he signed on to the series because he wanted “a steady job” to help pay alimony to his two exes — often complained that he hated the show’s unedited daily rushes.
He also griped that he “had a bad feeling” about the lack of chemistry on set, while the rest of the cast blasted his constant need for attention, the source said.
Meanwhile, a longtime friend said Williams was “hit hard” in May when CBS canceled the show, which paid him a reported $165,000 an episode, after just one season.
The pal told Britain’s Telegraph that Williams had wanted to stop making movies because they “brought out his demons” and he resented the idea of reprising his 1993 “Mrs. Doubtfire” role in a planned sequel.
“He signed up to do [movies & shows] purely out of necessity. He wasn’t poor, but the money wasn’t rolling in anymore and life is expensive when you have to pay off two ex-wives and have a family to support.”
But he reluctantly signed on to the project because he was desperate for cash, the friend said.
“Robin had promised himself he would not do any more [movies], as he invested so much in his roles that it left him drained and particularly vulnerable to depressive episodes,” the friend told the paper.
“He signed up to do them purely out of necessity. He wasn’t poor, but the money wasn’t rolling in anymore and life is expensive when you have to pay off two ex-wives and have a family to support.”
And a source told Radar Online that Williams was sleeping almost around the clock during his final days. “His bedroom had blackout curtains, because Robin didn’t want light in his bedroom,” the source said.
“He wasn’t eating and was just having problems getting out of bed. He would often complain that he was just so tired, even after sleeping 20 hours.”
Meanwhile, Broadway’s theaters dimmed their marquees for one minute Wednesday night in honor of Williams.
The actor starred in his own one-man Broadway show in 2002, and in 2011, acted the title role in the drama “Bengal Tiger at the Baghdad Zoo.”