Sofia Richie Dresses Up as a Sexy (and Pants-less) Santa for a Christmas Party with Scott Disick

Sofia Richie is ready to celebrate Christmas all night long!

The 19-year-old model got into the holiday spirit on Thursday night, dancing around the kitchen to her father Lionel Richie’s 1983 classic “All Night Long (All Night)” while dressed in some skin-showing Santa-themed themed sleepwear — minus the pants.

Her routine was put on for boyfriend Scott Disick, 34, who documented Sofia’s routine on his Instagram Stories.

Wearing a long-sleeve sweatshirt designed to mimic St. Nick’s classic red-and-white coat and black belt, Sofia appeared to be having the time of her life and she let loose. She paired the top with some white briefs and matching cozy socks.

Sofia and Disick appear happy as ever as they head into their first Christmas together.

The couple were first linked in May and have spent much of their time since then traveling, taking in trips to Miami, Venice, Milan, Puerto Vallarta and Los Cabos (to name a few).

A source recently told PEOPLE the two are “very serious” and that Sofia has been a positive influence on Disick, who has openly struggled with alcohol abuse and is the father to sons Mason, 8, Reign Aston, 3, and daughter Penelope, 5 — all with ex-girlfriend Kourtney Kardashian.

“[Sofia’s] been great for him,” the source said. “She’s made a big impact on his life and hasn’t partied at all since they met.”

“His friends adore her and nobody notices the age difference,” the source added. “She is very mature, she grew up in Hollywood and has always been in older situations. They seem really happy.”