The actor who played Screech on the 1990s TV show Saved by the Bell wants to use a concealed carry instructor as an expert at his trial next week.

Dustin Diamond is on trial for allegedly stabbing a man at a bar at Christmas. He was charged in January with one felony count of recklessly endangering safety and misdemeanour charges of carrying a concealed weapon and disorderly conduct.

The trial is scheduled for next week.

The 37-year-old Diamond has admitted he opened a small pocket knife after bar patrons struck his fiance. A judge wants to review expected testimony from the concealed carry instructor before allowing it at trial.

Diamond did not have a concealed carry permit.