Sydney Sweeney just leveled up to 28 — and her birthday blowout was outta this world, with celebs galore and her new flame Scooter Braun in full party mode.

The actress completely took over at her ‘Planet Syd’ bash at L.A.’s Vibiana on Sunday night … wearing the same sparkling mini dress Britney Spears wore for her “Circus” album shoot — and yes, even her onscreen flame Glen Powell tried to reach her orbit in a full-on NASA suit!

The guest list was astronomical, with Jeff Bezos and wife Lauren Sanchez making a stellar appearance after Sydney — and Scooter, separately — attended their June wedding.

Sydney’s IG pics show the galaxy of birthday chaos — twerking with Sexyy Red, belting karaoke with Wiz Khalifa, and a whole lot more.

The bash was legendary — her birthday was earlier this month, on the 12th — proving even after this year’s jeans ad turbulence, Sydney’s star-studded squad is still gravitating to her side!