Timothee Chalamet was a nervous wreck on the set of family drug drama Beautiful Boy, because he couldn't believe he was working alongside The Office star Steve Carell.

The Oscar nominee is obsessed with the U.S. version of Ricky Gervais' hit British comedy, which featured Carell as bumbling boss Michael Scott, so when he discovered they would be playing father and son in the new movie, Timothee had to try and keep his excitement under wraps.

"I was really nervous, I didn't want him to know (I was a huge fan)...," Timothee confessed on breakfast show Good Morning America. "I didn't want Steve to know because I thought he would be creeped out."

The Call Me by Your Name star's dream casting became all the more thrilling as Amy Ryan, who played Holly, Carell's onscreen girlfriend in The Office, was subsequently tapped to play his movie mum, and it was almost too much for Timothee to handle.

"I was constantly in a state of freaking out, especially when Amy and Steve were on set... because Michael and Holly were there," he smiled.

And while Steve really enjoyed reuniting with Amy in Beautiful Boy, getting their characters' relationship dynamic just right took some time to get used to, as this time, they were cast as exes.

"It was great (reuniting onscreen), but we play a divorced couple in this movie," Steve shared. "We naturally like each other so much (in real life) that the first scene where we have to embrace, it was way too warm for this divorced couple that still care about each other but don't just love each other, so we kinda clicked into Holly and Michael mode for a second, and had to pull back."

The American version of The Office ran from 2005 to 2013, and also made stars out of John Krasinski, Mindy Kaling, and Ed Helms, among others.

Beautiful Boy, directed by Felix Van Groeningen and co-produced by Brad Pitt, is set for release later this week (12Oct18).