Kate "Matthew and I wouldn't work."

It's one of the themes in Fool's Gold and a belief Kate Hudson holds in her own heart.

A year ago, soon after her split from musician Chris Robinson after seven years of marriage, Hudson took off for Australia to shoot the film.

"It was a difficult time for me," she says over a late breakfast at the Rose Cafe, after sleeping in at her nearby home. She orders a spinach omelet with egg whites, minus the Swiss cheese — wanting to look slim for a premiere later that week.

Taking off for five months was "probably the best thing I could have done," she says, "because there was just so much going on. It was good for all of us to be in a different place."

"Us" is Robinson and their 4-year-old son, Ryder.

Like her "foolish" character, Tess, who try as she might, just can't get her ex hubby, Finn (Matthew McConaughey), out of her head, Hudson has likewise remained close with Robinson.

"For me, the love changes form," says Hudson, 28, fiddling with her vintage tortoise-shell sunglasses she recently discovered in New York. "I have to remove myself for a little bit and ask for time with no contact."

After some distance, Robinson came with Ryder to visit her Down Under in Port Douglas. "Toward the end, the most difficult part was putting Ryder on that long flight back to Los Angeles," she recalls of the mother and son's three-week separation. "You zone out for those 14 hours, telling yourself he's fine. It's a lesson in letting things go. He was with his daddy and happy. But that transition for mothers is really hard."

Says Fool's Gold director Andy Tennant: "She was going through a tough time. Chris was down there quite a bit. It made it better for everybody that she had some sense of family and being a mom. Like most women who juggle career and family, she can turn on the Kate Hudson we all know when she's working, but when she's not, she's mom and watching out for her toddler."

Ryder, she says, is a very happy boy who has become a disciple of all things Star Wars, just like Hudson's older brother, actor Oliver Hudson (of CBS's Rules of Engagement), when he was a boy. In the bedroom they shared as kids, "Ollie" slept in his Star Wars sheets, while she snuggled in her Annie bedding.

When Hudson took Ryder to the FAO Schwarz store in New York over the winter, he "went out of his mind," she says. "He's all about his lightsabers. He got Yoda's lightsaber and the double Darth Maul one — pretty cool."

Though she prefers to have Ryder as close as possible during film shoots, she says some moms, like her own (Goldie Hawn), find it difficult to work with their kids around. "My mom was way more independent than I was," she recalls. "My mom traveled a lot and worked a lot, and she was way busier. And she wouldn't take us. When she was doing Private Benjamin, I remember she went away for three weeks and came back, and then went away for two weeks and came back."

Hudson's new constant on-set companion is Pomeranian Clara Bow, whom her ex-husband has dubbed "Delta Burke." She and Robinson share custody of their other two dogs: Doctor, a bulldog, and Bella, a mastiff she had given Robinson for a birthday.

For now, pets are preferable to paramours. The prospect of dating is totally unappealing. "I have no desire," she says, adding that she doesn't believe in exposing Ryder to men she introduces into her life. "If I go out, it's like once a month, and I end up in a tabloid with somebody lying about me. It's not fun, and it's not worth it."

Hudson sidesteps talking about former beau Owen Wilson, whom she visited after his suicide attempt, and explains it's too soon to discuss memories of her Four Feathers co-star, Heath Ledger. Hudson has found comfort in commiserating with Ledger's Brokeback Mountain co-star Ann Hathaway, her new friend and on-screen adversary in the soon-to-shoot comedy Bride Wars.

In both Bride Wars, due in 2009, and the comedy My Best Friend's Girl, scheduled for Sept. 19, Hudson plays an attorney. But in Fool's Gold, she is a simple servant on a yacht, and her ex-husband suddenly appears, in search of sunken treasure.

For their second on-screen go-around, the two learned to embrace their differences. "I drive her crazy," McConaughey acknowledges. "I've talked to her about being tardy. 'Come on, don't be tardy.' I always think I'm right; she always thinks she's right."

Just the idea of romancing McConaughey in real life causes Hudson to squirm just a bit in her chair. A "raunchy" sex scene they shot for the film (ultimately edited out) gave her a sense of how they'd fare as a couple.

"The fact that I couldn't stop laughing was a bad sign," she says. "He was making (grunting) sounds that I never heard of. No, Matthew and I wouldn't work."