Jennifer Lopez's stunning curves and glitter catsuit weren't the only things that stood out at a recent concert. The 43-year-old's twins, Max and Emme, joined their famous mother on stage at her concert in San Juan, Puerto Rico on Dec.23.

When one of the four-year-old twins, Emme, stepped up, Lopez scooped her up and held her in one arm. Emme's twin, Max, then came on stage and gave his mother a white rose.

Max, who was sharply dressed in a khaki jacket and white trousers, impressed the crowd when he handed his mother the rose and they began to clap after the surprising appearance.

View the photos Jennifer Lopez' twins Max and Emme on stage with her in Puerto Rico

Lopez's boyfriend, Casper Smart, 25, who performed with her as her backup dancer that night, joined his girlfriend and her kids on stage as well.

Lopez performed at a concert for her "Dance Again" world tour. The twins' father, Marc Anthony, joined her on stage on Dec. 21 to perform their duet "No me Ames" ("Don't Love Me").

And the exes appeared to get along well: Lopez put her arm around her ex-husband as they exited the stage.

According to a recent report, Anthony is not the only ex Lopez is still on friendly terms with. Her ex Ben Affleck, revealed that the two stars are still in touch with each other.

Affleck told the Hollywood Reporter that the former couple have the kind of relationship "where there'll be an email saying, 'Oh, your movie looks great.'"

The "Argo" star admitted that he congratulated the "Jenny From The Block" singer when she landed the multimillion-dollar judge gig on "American Idol."

"I remember when she got 'American Idol.' I said: 'This was really smart. Good luck.' I touch base. I respect her. I like her. She's put up with some stuff that was unfair in her life, and I'm really pleased to see her successful," Affleck said.

Tags: Jennifer Lopez celebrity babies Ben Affleck