Zach Braff put Jean Smart through “bong school” on the set of ‘Garden State’.

The ‘Scrubs’ actor, 49, wrote, directed and starred in his 2004 cult classic indie film about a depressed actor who returns to his home town and starts hanging out with his stoner friends while falling on love with kooky office worker Samantha, played by Natalie Portman, 43.

Actress Jean, 72, played Carol, the pot-smoking recovering alcoholic mother of Zach’s character’s friend Mark (Peter Sarsgaard) – and she has now told how she had never smoked pot from a bong before she had to film scenes doing so for the movie.

She told The Hollywood Reporter as part of an oral history record about making the movie: “I affectionately refer to my role as ‘Skank Mom’. I just thought the script was so amazing. I knew (Zach) was incredibly smart and clever, and I thought, ‘This will be really fun’.

“It was just one of those sets where it was fun to just wait for the next setup.

“Zach was teasing me so bad because I had never used a bong. I can’t believe that I’m admitting that since I went to college in the ’70s, but I had never smoked a bong.

“So he would make these big announcements: ‘Okay, after lunch break, I’m going to take Jean to bong school’.

“I had to learn a little lesson – a bong lesson. It was embarrassing.”

Zach recalled in the oral history collection of memories from making the film his then-girlfriend Bonnie Somerville, now 50, insisted Jean play Carol after working with the Hollywood character actress veteran on the NBC sitcom ‘In-Laws’.

He said: “I didn’t know Jean’s work that much at the time, but then I did a little research and I was like, ‘Wow, she’s perfect. Do you think she’d do it?’

“And Jean said yes. She was pitch perfect.”