Can your little nostalgic heart handle this?

At a recent performance during Backstreet Boys' Las Vegas residency, the group brought NSYNC's Joey Fatone up to the stage to serenade him with "Shape Of My Heart." Joey then took it upon himself to plant a wet one on Nick Carter in mid-song!

Ok, really, it was almost a full-blown make out session.

The group posted a video of the moment to Instagram showing Joey grabbing Nick's face and going in for the smooch, while the other members were on their knees.

You're tearin' up the shape of our hearts tonight @realjoeyfatone ❤️

A post shared by backstreetboys (@backstreetboys) on

"You're tearin' up the shape of our hearts tonight @realjoeyfatone ❤️," the caption read.

On March 9 the former NSYNC'er tweeted to the band, "You guys did a great job, proud of u guys! And nick u have great lips."

He also shared the Backstreet Boys' Instagram video, writing, "Thanks for making me feel like the prettiest girl in the room @backstreetboys ❤️"

Typically, during the song, the Boys bring a guest to the stage and serenade them while handing out roses.

At the end of the song, Backstreet Boys member AJ McLean also kissed Joey, but only on the cheek.

Over the years many have claimed BSB and NSYNC were rivals based on the fact they were both Orlando-based boy bands that really peaked around the same time.

Last year AJ said there was never really any bad blood between them.

"If anything, it might've been a healthy rivalry, but there never any competition. There was never any, you know, 'You guys suck!'" he said in 2016.

Nick and Joey have actually long acknowledged their friendship. Nick said Joey was the one who encouraged him to join "Dancing With the Stars" for Season 21 (Joey was in Season 4).

"I was really debating if I wanted to do it, and he said, 'It's a great experience, it keeps you in shape and it'll teach you a lot of stuff,'" Nick told Us Weekly in 2015.