The pair also showed off their impressively toned physiques on the sand.
The couple couldn't help but get a little hot and heavy as they shared a steamy kiss during a trip to Palm Beach in Sydney, Australia, on Wednesday. Kidman and Urban's trip came just a day after they celebrated Christmas with a series of PDA snaps.
On their beach trip, the 51-year-old actress -- who showed off her impressively toned physique in a black-and-white polka dot bikini -- leaned over for a passionate kiss with her beau, who was catching some rays in the sand. Urban, also 51, couldn't have looked to be in better spirits as he flaunted his own ripped bod on the beach.
Kidman's flirty beach look is worlds apart from her transformation for her latest movie, Destroyer, in which she plays former undercover cop Erin Bell. The Oscar winner is nearly unrecognizable in the film, so much so that she told ET it scared her and Urban's daughters, 10-year-old Sunday and 8-year-old Faith.
"They were a bit scared. They found it scary, yeah," Kidman admitted. "[My character is]... angry and she's defensive and she's on a mission and she has a lot of rage, but she also has a lot of pain and heart and is trying to fix the damage and heal things... I think that's very emotional, but it's a good story too."
"When it becomes in your home and you just kind of there, it's very gritty," Kidman noted, explaining that she completed a makeup test at home. "What happens is it becomes authentic, so then it just becomes, like, oh this is very real to me. I'm in this skin. I'm in this person. I'm not standing on the outside trying to make this happen."
See more in the video below.