Former High School Musical star Zac sent a sweet message to his model partner on Saturday, 5 September to mark the special day.
He wrote: "Happy anniversary baby. I love you."
Sami reciprocated by saying: "Time flies when you're having fun. Happy anniversary baby. I love you too."
In an interview earlier this year, model Sami admitted that dating someone in the public eye had taken some getting used to.
She told ELLE: "I've never spoken about us before, but, um, it's definitely different. I think that you have to take that [kind of attention] with a grain of salt, and put yourself in other people's positions. I think that's actually a really big part of it, putting yourself in their shoes, and trying to understand where they're coming from, and then it kinds of makes sense."
"It kind of just comes with the territory, and I know there's no really changing that, so you have to just embrace it."
Zac Efron (@ZacEfron) September 8, 2015