"I'm having a baby boy in the spring. I'll tell you -- it's June!" she told host Ellen DeGeneres.
Teigen and Legend already share 22-month-old daughter Luna Simone. The couple have yet to pick a name for their unborn son.
"Boy names are really tough," Teigen explained before quipping, "I don't even think he'll have a middle name because we can't even think of a first name."
"[With Luna], there was a blood moon happening," she said.
"It was a very beautiful night. Really big, vivid, red moon, and just gorgeous. I have this love for space, and I think about space camp all the time and my days at space camp as a youngster. I just thought Luna was perfect."
Teigen and Legend announced the model's pregnancy in November.
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