Christina Aguilera is the new face of Stephen Webster's jewelry campaign.

The Grammy winner poses in two Alfred Hitchcock-inspired ads, which debut in the April issue of W magazine.

"Stephen and I have been friends for many years and working together on this campaign and collection has been an incredible experience," Aguillera says.

"We shot it in August," Stephen tells Life & Style. "I got a call from her when she was on her world tour in Korea, and she told me she was pregnant. We'd originally planned to shoot the campaign in October or November, but we decided that the minute she got back from touring would be the best window of opportunity."

About four months pregnant at the time, Christina, 27, was already showing. "But it was okay," says Stephen. "The way we shot it, you wouldn't know. We weren't going for full-body shots."

Christina will soon start work on her next baby-inspired album. Should be interesting.