Jessica Simpson hit the Chateau Marmont to celebrate her Bday Thursday — and she had all eyes popping and tongues wagging in her sexy get-up.

The singer rolled up to L.A.’s famed West Hollywood hotspot to party with friends and family as she turned the Big 4-5.

But Jessica didn’t look a day over 25 — check out the Instagram photos, shared Friday from the girls’ get-together.

The mom of three sported a glittering see-through gown that exposed every inch of Jessica’s perfectly toned body. She also wore a silver bra, black panties and platform pumps topped off by a black overcoat. Oh, and let’s not forget the sparkling choker around her neck.

During her fun night out, Jessica posed for pics with her buddies — and her mom, Tina Ann, decked out in a leopard print dress.

In 2 other snaps, the birthday girl held up a two-tier cake and noshed on a cherry, writing in the caption, “Fancy dive into 45 💫✨💫”

One person who was MIA was Jessica’s estranged husband, Eric Johnson, who she split from in January after 10 years of marriage.