Mother-to-be FERGIE is determined to stay healthy during her pregnancy by maintaining a light workout plan and sipping on green juice to curb her cravings.

The Black Eyed Peas singer is expecting her first child with actor husband Josh Duhamel and while she is embracing her new body shape, she is refusing to give up exercising completely in a bid to keep her legs toned.

She tells InStyle magazine, "I walk on the treadmill for 25 minutes, at a 15 per cent incline and a 2.0 (miles-per-hour) speed. To really give my legs a workout, I do rotations, changing the position of my feet every five minutes - toes pointed inward to tone my inner thighs, outward to target my outer thighs, and straight on to work my glutes."

Fergie, 38, has also been keeping an eye on her diet - although she has been allowing herself to indulge in a good steak every now and then.

She says, "I eat a lot of lean protein, but lately I've been craving beef, so occasionally I'll have a grass-fed steak. I also drink juices made with greens or carrots... to curb my appetite between meals."

And she is feeling the effects of her healthy eating: "It's not just what you put on your skin; it's also what you put into your body. My skin looks better now than it did when I was a kid."