An off-duty FBI agent whose gun accidentally discharged when he did a back handspring at a wedding reception is facing an assault charge.

Chase Bishop, 29, reportedly surrendered on Tuesday in connection with the June 2 incident, which was captured on video.

He is due to appear on the charge on Wednesday.

A 24-year-old man was shot at the Mile High Spirits Tasting Room in Denver, after Mr Bishop’s gun flew out and discharged during the flip.

Mr Bishop will be arraigned on a charge of second-degree assault.

Denver officials said additional charges were possible pending the results of a blood-alcohol-content analysis, which could take another week.

Footage of the incident shows Mr Bishop dancing with a crowd around him when he suddenly thrusts himself backward onto his hands.

The gun is seen to slip out of his waistband and land on the dance floor.

It went off as Mr Bishop retrieved it.

-AAP