The 25-year-old singer took to Twitter and said Gomez's new single, which is coming out on June 22, is her "favourite thing ever," reported Hollywood Life.
"Guys on 6/22 @selenagomez is releasing my favorite thing she's ever done. Let's all get READY," the "Bad Blood" singer tweeted.
Gomez, 22, also posted a picture on Instagram thanking Swift.
"So excited to finally show you guys the art for #GoodForYou ft. @asvpxrocky coming 6/22! Thanks Tay! That's what friend's are for," she captioned the photo.