The two had celebrated Christmas early with her family, including her parents Billy Ray Cyrus and Tish Cyrus, earlier this week. On Friday, they partied with Liam's brother Chris Hemsworth and his wife Elsa Pataky.
Liam posted on his Instagram page a selfie of him and Miley wearing zany, red and green Christmas sweaters. Miley also sported a red and green light-up bow in her hair and a necklace of colorful lights.
"Happy birthday Jesus," the actor wrote.