Los Angeles, California - Olivia Rodrigo honored her rumored boyfriend, Louis Partridge, with a swoon-worthy message in celebration of his 21st birthday!

The Enola Holmes actor commemorated his big day with a throwback snap shared to Instagram on Monday, quickly earning some sweet praise from Olivia.

"welcome the 21 club angel boy!!!!" the singer wrote, adding on a few heart emojis as well.

Though the two have kept their romance relatively private, it doesn't seem to be much of a secret anymore!

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Louis was the first to address it directly while dishing on dating in the public eye earlier this year, sharing that he finds the pressure on her to be much "worse" than it is on him.

During her latest tour stops in the UK, Olivia has been paying homage to Louis with performances of so american – a GUTS (spilled) deluxe track that is not-so-subtlely inspired by the Brit, who has been in attendance at a number of shows on the tour so far.

Prior to sparking dating rumors with Louis last October, the get him back! artist was previously linked to DJ Zack Bia, producer Adam Faze, and her High School Musical: The Musical: The Series co-star Joshua Bassett.