Leylah Fernandez is putting the “ath” in athleisure thanks to a partnership with lululemon. She will serve as the fashion company’s brand ambassador starting this season.

“I've always felt my best in @lululemon and can't wait to get moving together,” the Canadian teen wrote on Instagram.

Fernandez is fresh off a colossal 2021, one that saw her reach her maiden major final at the US Open and play the first all-teen final in New York since Serena Williams overcame Martina Hingis in 1999.

Still just 19 years old, Fernandez previously wore ASICS on court.

“I'll be training, playing, and living in @lululemon from here on out,” Fernandez tweeted on Tuesday.

Starting off 2022 at a career-high ranking of No. 24, Fernandez made a winning return to action in Adelaide, defeating Ekaterina Alexandrova in straight sets before falling to 2020 Roland Garros champion Iga Swiatek.

Fernandez will be seeded at a Grand Slam tournament for the first time in Melbourne, where she will also aim to win her first main draw match Down under.