Selena Gomez celebrates 33rd birthday with a necklace featuring over 20 carats of diamonds

Diamonds for the birthday girl.

Over the weekend, Selena Gomez rang in 33 years around the sun, dazzling in a one-of-a-kind Brilliant Earth necklace featuring 20.39 carats of diamonds.

A rep for the brand tells Page Six Style the center pear-shaped stone clocked in at 5.05 carats alone.

The singer’s tennis necklace hails from the brand’s collaboration with British ethologist Jane Goodall, which launched last October.

Plus, we’re told the limited-edition one-of-a-kind piece will be auctioned off in September to benefit the Jane Goodall Institute — a nonprofit organization that supports wildlife research, education, and conservation.

Celebrating at a ’70s-themed party, Gomez added a groovy touch to the diamond necklace with a shaggy shearling coat and silver sequin Nadine Merabi jumpsuit ($615) with a plunging neckline and knot twist detailing on the front.

The Rare Beauty founder shared snaps from the lively evening on her Instagram, with a lengthy caption reflecting on the past year, which she said was the “most beautiful” of her life.

“As I step into this new year, I’m filled with excitement and hope for what’s to come,” Gomez wrote further down in the caption. “I look forward to sharing more moments with all of you, creating new memories, and continuing this beautiful journey together. MADLY LOVE YOU ALL 🥳”

All of Gomez’s loved ones came out to celebrate her, including her fiancé, Benny Blanco, and best friend, Taylor Swift.

In a photo, the “Love Story” singer posed next to her close pal, wearing what appears to be a black long-sleeved minidress.

Blanco, meanwhile, toasted to his bride-to-be in a black velvet blazer over a leopard-print button-up.