Taylor Hill/FilmMagic; Dave Benett/Getty
The 31-year-old actor popped up in a photo slideshow shared by Brooks' friend Michele Merkin this week, wishing the model a happy 23rd birthday.
In the third photo of the post — which Merkin captioned, "Wishing you croctails and giggles for life! #hbd #gg" — The Hunger Games actor could be seen behind the group, smiling while wearing a wide-brimmed hat.
Brooks expressed her appreciation for the sweet sentiment, writing to Merkin in a comment, "Agh I love you so much. GG4L!! ❤️."
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Michele merkin/ instagram
Hemsworth and Brooks were first spotted together in December 2019 for a brunch with the actor's parents, Craig and Leonie, in Byron Bay, New South Wales, Australia.
Since then, the two have been spotted out together frequently, kissing on a beach in their home country, enjoying casual Malibu dates during a trip back to America and spending quiet nights at home playing Scrabble games while staying in amid the coronavirus pandemic.
Late last summer, they were photographed enjoying a hike to the Byron Bay Lighthouse, walking barefoot as they headed toward their destination.
"Liam and Gabriella have spent a lot of time in Australia together," a source told PEOPLE of the duo in January 2020, adding at the time that they were "getting serious."
RELATED VIDEO: Liam Hemsworth and Girlfriend Gabriella Brooks Soak Up the Sun in Australia
This is the first public relationship Hemsworth has been in since his split from ex-wife Miley Cyrus. The former couple wed in December 2018 after meeting 10 years prior, but split months later, with Hemsworth filing for divorce in August 2019.
Hemsworth's marital status was officially classified as single on Feb. 22, 2020, according to legal documents obtained by PEOPLE the previous month.
Cyrus, 28, went on to have relationships with Kaitlynn Carter and Cody Simpson. In March, she was spotted getting cozy with Yungblud at the Rainbow Bar & Grill in West Hollywood, California, as seen in photographs obtained by The Daily Mail.
But a source told PEOPLE at the time that Cyrus and Yungblud (née Dominic Harrison), 23, were "just friends" and spending time with a group of pals.