Jennifer Lopez freaked out when her son cut his chin open.

The 'Dance Again' singer - who shares five-year-old twins Max and Emme with her ex-husband Marc Anthony - admits she was very worried about the little boy, who she has nicknamed 'The Boss', when he fell recently and needed stitches until he started laughing about his injury.

The 43-year-old singer and actress told ''I hear that all little boys have a scar on their chin. Of course, I was freaking out, but he was fine. He said it tickled.''

Jennifer spent time in Las Vegas this weekend, where she attended the grand opening of the new club Hakkasan inside the MGM Grand hotel with her ex-husband Marc and her boyfriend of more than one year Casper Smart.

Other guests included Vanessa Hudgens and Calvin Harris.

She said: ''It's a little night off from being a mom and that's exciting. It's nice to have a little down time.''

The former couple have remained friends since their split in 2011.

Marc recently parted ways with his girlfriend Chloe Green.

The 44-year-old star is said to have ended his relationship with the Topshop heiress despite her already spending a lot of time with his five children.

An insider previously said: ''It seems to be Marc's decision to end it. She's already moved her stuff from his house in Miami and has gone away with friends to get over it.

''Things happened very quickly between them -- and she'd spent a lot of time with his children.''