The Toxic hitmaker, who has been linked to the personal trainer since November (16), made an appearance on Asghari's Instagram account on Sunday night as the pair appeared to cuddle up in bed.

In the short video, Britney and Sam used the app's reindeer filter, which gave their images animated reindeer ears and antlers and altered the sound of their voices.

"Merry Christmas," she told his followers. "Merry Christmas to all and to all a goodnight."

It's not the first time the singer has popped up on Sam's social media page - the dating speculation first surfaced last month (Nov16), after he shared a snap of himself and Britney out together in Los Angeles. He promptly deleted the image.

Sam and Britney are believed to have met while filming the racy video for the pop superstar's latest single, Slumber Party, in which he played the mother-of-two's love interest.

It's the 35-year-old's first serious relationship since she split from her last boyfriend, producer Charlie Ebersol, in June, 2015. She also dated David Lucado, and was engaged to agent Jason Trawick until their split in 2013.

Sam wasn't the only man Britney appeared to spend the holidays with - she also enjoyed some down time with her family, and posted a photo of her sons Sean Preston, 11, and Jayden James, 10, in camouflage gear, enjoying a day of outdoor adventures.

"Some good hunting and zip lining for the holidays!," she captioned the snap, uploaded on Sunday. "Merry Christmas!!"

The boys are Britney's two children from her marriage to dancer Kevin Federline, who she was married to from 2004 to 2007.

The festive posts both appeared online hours before Spears was targeted in an Internet death hoax, after hackers gained access to the official Twitter account of Sony Music Global and falsely reported her passing.

Her manager has since assured fans Britney is "fine and well".