Normal People stars Paul Mescal and Daisy Edgar Jones are close mates as well as on-screen lovers.
Heartthrob Paul, who portrays Connell across from Daisy's Marianne, shared a sweet birthday post for his co-star featuring a string of behind-the-scenes snaps from the show.
They showed Daisy getting her makeup touched up, the two of them sat laughing over coffee, Daisy laughing on a doorstep, and her beaming at him during a press junket.
"Happy birthday to this LEGEND!" Paul wrote, "@daisyedgarjones you are one of a kind.
"Have the best day ever."
Daisy replied: "THANK YOU PAULIO."
The BBC adaptation of Sally Rooney's bestseller has become hugely popular, with fans convinced that Paul and Daisy would make a great real life couple.
One bluntly commented on the post: "You should marry her."
Another laughed: "Literally the only onscreen couple I've ever wanted to be together off screen! My obsession with Normal People is very unhealthy!"
"OMG my heart" a third penned, "You guys are precious!"
After the massive response to the first series, it's reported that the BBC has set its heart on a second entry.
A source told the Mirror : "The BBC are desperate to get going on series two.
"The viewing numbers are huge and they want more of the same. They want to strike while the iron is hot and get working on the series as soon as possible.
"Their hope is to roll out the series in a similar time frame to Killing Eve, but it all depends on if they can get Sally Rooney on board."
Meanwhile, Paul's responded to rumours that he's in the running to be the next 007, saying to portray Bond would "be a dream come true."
"Well, I'd be rich!" he chuckled.
Paul added: "I knew Normal People was a huge deal, but I really didn't expect this."
