The unlikely couple, who has been vacationing together in Ibiza, enjoyed a cozy dinner out with a few pals, including Joan Smalls and Mohammed Al Turki, who has been a regular member of the lovebirds' entourage.
"@harry_brant's 18th birthday with our #ibizafam @joansmalls @petermbrant @afefjay @afefjnifen @mrodofficial and @zacefron, #SeperationAnexiety," Turki captioned the pic, which was regrammed by the 26-year-old fashion model.
In the black-and-white shot, Zac holds on to his ladylove's arm while sticking his tongue out and flashing a silly face at the camera. Meanwhile, Rodriguez is beaming from ear to ear, clearly ecstatic to be in the company of the former Disney darling.
Efron and Rodriguez reunited last week in Ibiza just several weeks after they were first caught making out and engaging in some hot and heavy PDA during a trip to Sardinia. Over the weekend, the couple was spotted kissing again in addition to partying on Justin Bieber's yacht, where they clearly had no qualms putting their romance on full display.
The pair also attended Riccardo Tisci's 40th birthday bash on Friday, and naturally, Turki shared a pic from the party, in which Efron is wrapping his arm around Michelle as they pose with a group of pals, including Paris Hilton.
Following the first PDA-packed sighting of the surprising couple in early July, a source revealed that the two have a history of hooking up after they were introduced by Mohammed Al Turki on a vacation abroad two years ago.
"Michelle is super-cool and laid-back, and Zac has always been attracted to her because of that," the source said. "She's one of those people that everyone likes, she just gets on with all kinds of people and doesn't take the fame thing too seriously."
"Zac likes the fact that she is laid-back and he can relate to her," the insider added. "He is attracted to her great attitude. They understand one another."