Angelina Jolie, pregnant with twins, has some secrets for staying serene at the hectic Cannes Film Festival: get Brad Pitt to babysit sometimes, and wear comfy shoes on the red carpet.

Jolie was at the Cannes Film Festival on Thursday to promote DreamWorks' animated Kung Fu Panda. She'll be busy at Cannes, as she also stars in another movie here, Clint Eastwood's Changeling.

But the mother of four - soon to be six - swears she's not working too hard.

"I'm sitting and talking a lot, and everybody's being very nice to me," the Mr & Mrs Smith actress told reporters at a news conference. "If I was feeling too pregnant, everybody said I didn't have to come."

The 32-year-old actress also confirmed that she is thinking about giving birth in France.

"I actually haven't completely decided, but we are certainly thinking of France," Jolie said.

"It's a second language in our house. I'm still learning so I'm not going to attempt it here today, my rusty French. But our children are starting to speak French, so being here is very good for them for their language."

In Cannes, while Jolie was swarmed by photographers at a photo shoot, Brad Pitt was taking care of the couple's children. He was joining her later on Cannes' red carpet for the Kung Fu Panda premiere: "He's with our kids right now, but he'll get his suit on at the last minute, I'm sure," Jolie added.

She also revealed a red carpet beauty secret.

"I'm going to do a shoe ad right now - Cole Haan makes a shoe with a Nike sole, so I have a low heel with a Nike sole," she said.

Jolie provides the voice of an assertive tigress and martial arts maestro in Kung Fu Panda, while Jack Black is the pudgy title character. Dustin Hoffman gives voice to a kung fu master who helps train the clumsy panda to live up to his potential.

Jolie may play a tigress on screen, but the actress swears she's not a fierce feline at home with Pitt.

"I think I have a very even partner right now, and I think we're very balanced at home with our power-sharing," she said. "But I think every woman in some way is a tigress or would like to be."

Most questions at the news conference focused on Jolie, but Hoffman managed to get a few quips in.

"I just want to say one thing because no one has asked the question - there was a point in time when Angelina could have chosen between me and Brad," Hoffman joked.

The cast of Kung Fu Panda chatted with reporters a day after Black let slip during a Today show interview that Jolie would soon be a mother of six. Black gave the news away when he said Jolie would "have as many as (the) 'Brady Bunch'".

Asked to confirm the news to Cannes' press corps, Jolie turned to Black.

"Jack, would you like to?" she quipped, before adding: "Yes, yes, they are twins."