Chrissy Teigen was undergoing IVF treatment during her Sports Illustrated Swimsuit shoot
The 'Lip Sync Battle' star - who will give birth to her first child with husband John Legend in April - admits it was "hard" posing for the sexy pictures because of the side effects from the injections she had to have as part of her fertility treatment.
She said: "I was doing IVF during the shoot. I was getting my shots and everything in Zanzibar, I had a little medical kit.
"It was hard because you bloat from it, and you bruise - if I hit the wrong area.
"That's the kind of things we had to cover with make-up."
The 30-year-old beauty admits she would have "definitely" done the same shoot with her bump on show, though she and the 'All of Me' singer aren't interested in having personal pictures of her posing while pregnant.
She told People magazine: "John and I aren't the kind of people to have photo of ourselves in our house, like embracing the pregnant and naked thing. But if it were for a cool magazine and beautifully done, I would do that...[SI Swim], I would have definitely done pregnant!"
This year's SI covers feature three different models and Chrissy - who was part of a triple-cover when she fronted the annual issue - thinks they are "very fun".
She said: "I have to say - I always wanted multiple covers. When I was on the cover, I didn't want it to be any other picture, I loved the multiple girls, I think there's something very fun about it."
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