But Anna Paquin's True Blood co-star was confined to the sidelines as the Canadian actress planted a smacker on a friendly dolphin during a trip to a sea life centre.
Anna - who turned 27 last week - spent the day with Stephen at the San Diego attraction where the couple got acquainted with some of the residents, including a cute two-week-old penguin chick.
They were in the city to promote their vampire series. In it Anna plays telepathic, waitress Sookie Stackhouse, who falls for the charms of handsome vampire Bill Compton - Steve's character.
While filming the first season, Anna and Stephen started a real-life romance, which they tried to keep under wraps. When they eventually went public it was, says Anna, "the worst kept secret on the planet".
The Oscar-winning actress is also a firm fixture in the lives of 39-year-old Stephen's two children, nine-year-old Billy and Lilac, seven, from previous relationships.
But as to the question of whether she's likely to have her own children with the Essex-born actor, Anna says the time isn't quite right.
She's not ruling out the possibility of starting a family sometime in the future, however.
"I don’t know how they'd resolve me and my short shorts on the show with a baby bump," she said, referring to the fact that her character is never seen in anything other than shorts.
"So there are a few 'not untils' on that one. At some point, when that convenient time, which never exists for actresses, comes – somewhere between now and menopause - I will. I have time."