llen Berezovsky/Getty; Steve Granitz/WireImage
“I love this handsome human so much!” Theron, 45, wrote on Instagram alongside an old photo of the pair in honor of Reeves’ 56th birthday Wednesday. “Happy birthday, Keanu. You’re just the best!”
Theron and Reeves starred together in 1997’s The Devil’s Advocate, as well as Sweet November in 2001.
Many fans used Theron’s post as an opportunity to push for another movie collaboration. “When is the atomic blonde/john wick crossover happening??” one commented, while another similarly added, “A John Wick and the Atomic Blonde crossover would be epic 🙌”
Others commented on how great the pair of actors look together, though Reeves is already taken by artist Alexandra Grant. “I’d always hoped you two would get married in real life. You have great on-screen chemistry and look so cute together!” an Instagram user wrote of Theron and the Marriage Story actor.
Reeves only recently went public with his relationship with Grant, stepping out for the first time together at the LACMA Art + Film Gala in November 2019.
The actor and the artist have been friends for years, and even collaborated on works together such as Reeves' 2011 book Ode to Happiness and 2016’s Shadows, which was also written by Reeves with illustrations by Grant.
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Reeves and Grant made their public debut as a couple in November
The pair have also founded X Artists’ Books, a publishing house which they established in 2017.
Grant addressed her romance with Reeves for the first time in March, opening up to Vogue about the attention she received once they went public with their relationship.
"I think every single person I knew called me in the first week of November, and that’s fascinating,” the artist said. "But the question I’ve been asking in all of this is: 'What is the opportunity for good?'"
Grant was also asked in the Vogue interview if marriage was something she could foresee for herself in the future.
Alexandra Grant and Keanu Reeves
"Over a glass of wine… I would love to tell you,” she joked at the time. "Love at every level is deeply important to my identity. How’s that for dodging the question? I do not believe that isolation is the way. There is a period of isolation that I do as a painter, but I deeply value the experience of being in relationships."
While Reeves has yet to address his romance with Grant, a source told PEOPLE back in November that the Matrix 4 star was ready to be more public with his relationship.
“Keanu wants to openly share his life with her,” a source said. “He is extremely happy and grateful to have Alex in his life.”