The pop star was in the middle of a performance of Crazy when a man did what appeared to be a somersault towards her entourage.
He is then seen being pursued by a member of the security team.
The video shows him throwing the guard over his head before being wrestled to the floor by the singer’s dancers.
The star, who looks visibly worried, says “Is everything okay, what’s going on?” and was then heard saying “He’s got a gun?” according to TMZ.
She is then surrounded by other members of the security staff and is escorted off stage as the man is bundled, struggling, in the opposite direction.
The US star was performing on a leg of her Piece of Me tour at the Planet Hollywood venue.
Police named the man arrested as 37-year-old Jesse Webb.
TMZ reported he was acting in a disorderly manner during the show and was asked to leave, at which point he leaped on stage.
No weapons were found on him, the website said.