A day after Chrissy Teigen and husband John Legend announced they were expecting a third child, Teigen revealed in a series of tweets how she found out about the surprise pregnancy.

When one of her more than 13 million Twitter followers asked if she knew she was pregnant during her breast implant removal surgery in June, the model tweeted Friday that “It’s quite a story.”

“I did the routine pregnancy test you do before surgery. It said negative. It was not negative,” the Cravings author wrote, adding she took another test after the June 19 surgery.

“I was scared s–tless … was pretty positive you shouldn’t get your boobs out while pregnant.”

The tweets came a day after Teigen and Legend announced the pregnancy in his new music video, “Wild.” The video includes a close-up shot on her growing baby bump.

Teigen said she was surprised and “didn’t think” she could get pregnant naturally, without the aid of fertility treatments. The couple’s other children — Luna, four, and Miles, two — were conceived after undergoing IVF treatments.

“Luna is very, very excited. Miles, not so much. Jealous!,” Teigen wrote after admitting she was nervous about the pregnancy.

“Part of me misses the safety of my perfect embryos, created in their little dish. They felt untouchable and safe. Now I feel a bit…eggshelly,” she tweeted.