Behind The Scenes: Kate's Wild Photo shoot

Hudson headed to Africa with famed photographer Peter Lindbergh to shoot the ad campaign for her new eco-friendly haircare line, David Babaii for WildAid (done in partnership with her longtime hairdresser). "We have a blast together," she says of Babaii. "I'm just lucky to have him as my companion while I travel and work."

Hudson, whose line will donate 10 percent of all sales to WildAid, shares camera time with a cheetah. She tells PEOPLE, "I really have a thing about natural product. It's very difficult to make things that are completely organic and sustainable. David and I got so excited about making something like that. Making something conscious and making it good."

Of the shoot, Hudson tells PEOPLE that working with a cheetah was "the most fun. He was purring. I remember listening to it and [asking], 'Should I be running right now because his purr sounds more like a growl?' But they're like, 'No. He's just super happy.' And I got really comfortable with it. And I would literally lay on the cheetah. It was really pretty cool."

The self-described "low-maintenance" star credits Babaii with keeping her blonde locks looking fabulous. "I'm really not good at doing my own hair," she admits to PEOPLE, relying on "sleep and water" to look good otherwise.

Babaii makes sure Hudson's hair is flawless for the cameras. "It's so great collaborating with Kate," he says. "I adore her. She's my muse and inspiration. We get in trouble all the time."

At the wildlife preserve, mom Hudson also bonded with some little ones – lion cubs! "Even though they're babies, they are lions. They were very sweet. I would put them on their back and rub their tummy. And they would love it!"