Normally camera shy it seems like Ashton Kutcher and Mila Kunis just could not help engaging in some PDA while on vacation in St. Tropez. The couple was spotted kissing as the walked hand-in-hand following a boat ride.

The former "That 70's Show" stars were accompanied by their royal pal Princess Beatrice and her boyfriend Dave Clark.

According to the Daily Mail, "the 35-year-old was seen leaning in and planting a kiss on the actress, 29, as the pair walked hand-in-hand following a boat ride with the royal and her friends in the French Riviera town."

Typically, the couple seems as if they are in a bad mood when ever they go out in public. This is of course due to the constant flashes from cameras in their faces but the day on the beach was different for them.

[For photos of Ashton Kutcher and Mila Kunis on their vacation click HERE]

Kutcher and Kunis actually looked content and happy to be out in the company of their friends.

The actor who is often seen in casual wear such as a hoodie and jeans, dressed for the occasion in beige pants, an orange shirt, and blue and white jacket paired with a white sunhat.

Meanwhile his girlfriend kept things casual with skinny jeans, a navy sweater with a white picture of a giraffe and flip flops.

She pulled her long brown hair in a high ponytail and hid behind her brown aviator sunglasses.

Last month the Hollywood couple began to be spotted hanging out with the Princess and her boyfriend.  The Daily Mail reported that the foursome has moved from acquaintances to much more as the royal and her beau invited the two to join them on vacation.

With the actress having the weekend off from filming her upcoming movie "Jupiter Ascending," the pair flew from London to Nice to join Princess Beatrice and Dave for a group vacation in St Tropez.

For more Ashton Kutcher and mIla Kunis news click HERE.