Lorde's celebrity friends even sang her Happy Birthday as she blew out the candles on her cake.
Swift also made a hand-decorated card and posted a heartfelt message to social media in honour of Lorde's birthday.
And it wasn't just any old Birthday message either, Swift took the opportunity to reminisce over the first time they got together to hang out in New York.
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"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," the 26-year-old shared via Instagram.
"I. Love. You. So. Much. Ella. (sic)" Taylor wrote in her post to Lorde, whose real name is Ella Yelich-O'Connor.
While Taylor's been under the spotlight for her relationship dramas this year and Lorde's come under fire for taking so long to release her follow up to Pure Heroine, the pair seem to have stuck together through it all.
Lorde also took to social media to celebrate her birthday and give fans an update on the upcoming album, saying "You'll have to hold on. The big day is not tomorrow, or even next month realistically, but soon. I know you understand."