Zanessa @ 'HSM2' London Premiere

On-and-off-screen couple Zac Efron and Vanessa Hudgens look like tween royalty at the European premiere of High School Musical 2 at London’s O2 Arena on Sunday.

Vanessa paired her stunning strapless floor-grazing gown by Trina Turk with silver Prada mules while Zac wore his pride for London with a navy jacket with a UK flag inner-lining (aka Union Jack jacket).

Zac, 19, recently told People he can’t remember the first time kissing Vanessa, 18.

“I truly didn’t realize that there was not a kiss. It never stuck out to me,” he says.

V recalls there was a kiss, but “on the cheek [and] that’s as far as we got.”

“You guys, your memories are failing you,” director/choreographer Kenny Ortega said Friday at a press conference in London to promote High School Musical 2. “I went to their parents and asked for permission. I went to Vanessa‘s mom first, and then to Zac‘s mom second and said, ‘Do you mind if I request a kiss in the event that we want to use it for the end of the film?’ And we did it. Then, we all sort of decided that this wasn’t about that.”

“You seemed to enjoy it though,” Ortega said to Zac, who blushed but didn’t deny the comment. (The kiss never made the cut for the first film.)

20+ pictures inside of Zanessa in London…