Justin & Jessica's Makeout Marathon

Justin Timberlake and Jessica Biel are still a perfect SET!

Though the two have kept an ultra-low profile in recent months, it doesn’t mean there’s any trouble in paradise – and they definitely proved it Friday night!

Joined by a group of friends, Justin and Jess invaded the VIP area at Miami’s SET nightclub around 12:30 a.m. Friday evening, an eyewitness tells OK!. While their pals couldn’t keep their hands off the overflowing Grey Goose and Patron in the room, the lovebirds couldn’t keep their hands off each other!

“They were showing a lot of PDA!” the eyewitness tells OK!. “It was a lot – considering how coy most celebrity couples are.”

Dressed in casually – she in a breezy ethnic blouse and short skirt; he, jeans and T-shirt – the couple of nearly a year and a half engaged in a marathon of hugging, French kissing, hand-holding, dancing, singing, and gazing into each others’ eyes, the source adds.

”You couldn’t tell them apart,” the source says. “They only had eyes for each other. They told friends they just wanted to have fun that night – no photos, no media, just a private table where they could let loose.”

And apparently that they did.

By the time J&J exited SET – hand-in-hand, of course – at 3:30 a.m., they were still as giddy as ever.

“They were telling friends they had the best time,” the source says.