Heidi Klum thinks about her boyfriend during lingerie shoots.

The 42-year-old supermodel - who has her own underwear line entitled Heidi Klum Intimates - models for the collection's campaigns herself and confessed she keeps her boyfriend Vito Schnabel, 27, in her mind while she's on set.

Asked how she stayed focussed while shooting the most recent stunning stills, which were captured by Francesco Carrozzini, she said: ''I remember when I first started shooting swimwear and lingerie, and the advice photographers always gave me was to not over-pose.

''No overarching, duck faces or strange poses so it doesn't look like you are trying too hard. Even though [photographer] Francesco Carrozzini is behind the camera, I look into the lens and I think about my boyfriend.''

The blonde beauty added she doesn't believe in getting in shape for a particular job and prefers to keep her body in peak physical condition at all times.

She explained: ''I don't really have a ritual before I shoot. I like looking fit all the time - not just for a shoot - as you never know when your clothes come off! When I first started modeling 20 years ago, I had to make some overall lifestyle changes.

''It's been a big part of my job to make sure that I'm fit on a regular basis. For me, that means drinking a lot of water, eating super healthy and making sure I sleep eight hours a day. That doesn't always work with my schedule, but I try! I also try to hit the treadmill 2-3 times a week.''

However, Heidi refuses to take all the credit for her new campaign and praised Carrozzini's ability to set the mood on set for helping them achieve the perfect shot.

She told PEOPLE: ''He has a way of making everything look effortlessly sexy.

''He keeps the set very minimal and plays great music. We just kind of get in the zone relaxing on a couch or rolling around on a carpet on the floor. I always know when we have the shot and then we move onto the next one.''