The bloodied T-shirt and sweater and damaged coat Casey Smet wore on the night of the clash was shown in court on Thursday (28May15) as part of the prosecutor's evidence against the former Saved By The Bell star, who denies a felony charge of reckless endangerment and disorderly conduct and carrying a concealed weapon misdemeanours.

During the second day of Diamond's trial, Smet told the court he had no idea he had been stabbed until after he left the bar in Port Washington. He told police at the time he didn't recognise his alleged attacker, but could point him out.

The 25 year old testified, "Before the altercation, I was not bleeding or stabbed. After the altercation, I was."

Smet's cousin, Bethany Ward, also took the stand on Thursday, revealing the fight started after Smet stumbled and bumped into Diamond's fiancee, Amanda Schutz.

Schutz, who is facing a misdemeanour disorderly conduct count, reportedly grabbed the woman's hand as she and Smet tried to leave, and when she refused to let go, Ward punched her.

A fight then broke out around them, during which Diamond reportedly pulled a knife on Smet.

The actor, 38, maintains he acted in self-defence, while his lawyers claim security footage of the bust-up is too grainy to determine who actually stabbed Smet.

Schutz has also pleaded not guilty to her involvement in the brawl.

The trial continues.