And despite saying in an interview with Ryan Seacrest March 22 that he and the Roommate actress were "friends -- and that's all there is to it," the pair packed on the PDA while enjoying their little getaway down under.
On Tuesday, Valderrama, 32, and Kelly, 31, strolled through Balmoral with their arms wrapped tightly around each other. They shared a warm gaze into each other's eyes and looked totally comfortable and at ease.
In addition to making his debut with the brunette beauty, the That 70s Show actor also acknowledged their connection for the first time publicly.
"Homies & Homiettes boat cruising in Sydney," he posted to his Instgram Tuesday while tweeting at Kelly.
In March, Us Weekly exclusively reported that the pair were spotted "kissing and grinding" at West Hollywood's Greystone Manor Supperclub. They also dined at L.A.'s Pink Taco eatery that month and visited Disneyland in Anaheim in February.
Valderrama has most recently been linked to on-again, off again love Demi Lovato while Kelly and her New York Yankees beau of three years Derek Jeter split in August.