Justin Bieber, Billie Eilish, Martha Stewart And More Party After Grammys

Music’s biggest stars weren’t ready to call it a night after the Grammys ... instead, flocking to some of L.A.’s hottest spots to keep the celebration rolling.

One of the buzziest bashes went down at the Beverly Hills Hotel ... drawing stars like Justin Bieber, Lauryn Hill, Jamie Foxx, and more. In video from inside the party, Bieber is still showing off his bare chest -- strutting through the crowd in an open-faced hoodie, hands planted on a friend’s shoulders as he bops along to Kanye West’s “Gold Digger.”

Lauryn Hill was soaking up major love after her standout performance earlier in the night ... with the MC crowning her a “snow leopard” -- a term for an attractive older woman.

Foxx -- in a colorful suit and large top hat -- was seen moving and grooving to his hit "Blame It" before grabbing the mic for what looked like a spur-of-the-moment performance.

Meanwhile, more stars were throwing down at Universal Music's after-party in Hollywood ... including Lola Young, Sharon & Jack Osboure, J Balvin, Huntrix, and Martha Stewart. Inside footage of the bash shows Shania Twain stepping to the beat, while Paris Jackson was spotted mingling with fellow partygoers.