British actor Rupert Grint made a theatre-goer vomit during his recent West End run.

The Harry Potter star appeared as a drug-addled criminal in Jez Butterworth's gritty play Mojo from October (13) to February (14), and he reveals one particularly graphic scene produced an extreme reaction from a member of the audience.

He tells Britain's Radar magazine, "There is one part of the play where I'm dry-retching, and in reaction to that, one night someone was sick in the front row."

However, Grint is able to laugh off the incident, adding, "I know that everyone's a critic these days, but I can assure you that it wasn't a reviewer having an extreme response to the play."