Actor Christian Slater has given the cast and crew of Off-Broadway show Heathers a big thumbs up after taking in the musical adaptation of his cult film on Wednesday night (02Apr14).

The stage version of the 1989 black comedy, which co-starred Winona Ryder as lead character Veronica, who battles against a clique of mean schoolgirls, opened to mixed reviews on Monday (31Mar14), with critics describing the production as "lively" and "goofy", yet "sloppy".

Slater decided to check out the show for himself on Wednesday and he has given the production his seal of approval, although he admits it was "weird" watching actor Ryan MCCartan portray his character Jason 'J.D.' Dean.

Speaking on U.S. breakfast show Today on Thursday (03Apr14), he says, "I enjoyed it. It was weird; it was weird to see that show, a musical version, but it was adorable. Director Andy Fickman did a great job and the cast is funny.

"What was weird was just seeing another guy up there, in the black jacket, playing that part... There were parts of me that wanted to run up on the stage... go up there (and take over)..."

The Broken Arrow star reveals he didn't want to distract the cast by making a big entrance, so he didn't make his presence known until after the final curtain call.

He adds, "I snuck in (to the theatre) and then showed up at the end (to meet the cast). It worked out great."