Jennifer Lopez appears to be smitten with her new lover and spent a romantic night in Las Vegas with him on Monday.

The 42-year-old performer and her boyfriend Casper Smart were seen at pan-Asian restaurant Social House inside Vegas' City Center, where they were joined by Jennifer's American Idol colleagues Steven Tyler, Randy Jackson and Ryan Seacrest.

The gang were in Sin City to tape an episode for the upcoming season of the talent show and grabbed a bite together in the evening.

But it was the mother-of-two and her 24-year-old boyfriend who apparently put on a show.

They all arrived to the restaurant around 8pm and ordered pizza, Kobe hanger steak and yellowtail as well as Caymus cabernet wine.

An eyewitness told E! Online that Jennifer and her backing dancer beau were cuddled up together throughout the meal and couldn't resist exchanging a few kisses during the 90 minute dinner.

After everyone had finished their entrées, Casper apparently surprised Jennifer by ordering the dark chocolate lava cake for her for dessert.

The Jenny From The Block singer was apparently not able to finish the decadent treat and the other guys on the table piled in to try it.

Just the day before the couple were seen out together in Calabasas, California, where they went shopping.