Taylor Swift, Lena Dunham and Aziz Ansari Party at Lorde's 20th Birthday in NYC: Pics!

Lorde was treated like royalty for her birthday!

Lorde has left her teens behind!

On Monday night, the "Royals" singer, whose real name is Ella Marija Lani Yelich-O’Connor, celebrated her 20th birthday with some of her closest pals in New York City. The gathering was orchestrated by longtime bestie, Taylor Swift, and celebrity guests included Karlie Kloss, Aziz Ansari, Lena Dunham, Mae Whitman, and Rachel Antonoff.

MORE: EXCLUSIVE: Elle King On How She Wound Up Partying With Taylor Swift, Wanting to 'Celebrate Love' on Tour

Red and gold balloons covered the ceiling of the party, and a cake was brought out in Lorde’s honor as her friends all sang. There were also several giant gold balloons that spelled out: “U R 20.”

The Australian singer-songwriter took to Instagram to thank Swift, 26, for the soiree, posting several photos.

“Had the best birthday party I've ever had tonight surrounded by my NYC family,” she wrote. “All organized by Tay, who is as she says ‘a mom with no kids.' I am your kid and you love me so hard, I could burst. Here's to our three magic years of best friendship and more moments like this squished between angels.”

Swift mirrored the sentiment, posting a photo of a hand-drawn birthday card for her friend, writing: “Thank you for the music you make, the advice you give, the thoughts you provoke, and the way you've made my life more beautiful since the first day we met up in New York and ate burgers on a park bench and got attacked by squirrels. I. Love. You. So. Much. Ella.@lordemusic.”

The GRAMMY winner also shared an image of herself and Kloss kissing Lorde on the cheek, and another one of herself and Ansari posing in their matching cat sweaters.

MORE: Drake Fuels Romance Rumors With Taylor Swift Photo From His Birthday Party

The “Blank Space” crooner attended the bash in a leopard print coat with her brother, Austin, by her side.

Prior to her party, Lorde posted a lengthy message to Facebook about her milestone birthday, opening up to her fans.

“If I’m being real with myself, in some ways I stopped feeling like a teenager a while ago,” she wrote. “Sometime in the last year or so, part of me crossed over. For one thing, I made a very deliberate choice to withdraw for a little while from a public life. I haven’t had my hair or makeup done in a year, the free handbags dried up LONG ago, and the paparazzi at the airport are almost always for someone else. And let me tell you, as much as I love being full noise album cycle girl, it's been a motherf**king joy.”

For more on Tay’s squad outings, watch the clip below!