Why Chrissy Teigen Isn't Ready to Confirm Her Baby's Sex — Yet: 'We Did the Harvesting' Again

Chrissy Teigen and John Legend‘s family is expanding, and while the couple has shared their baby joy with the world, they’re keeping some details private — for now.

The 32-year-old model told PEOPLE Wednesday of her second child’s sex while at a junket for Lip Sync Battle LIVE: A Michael Jackson Celebration, “We’re not ready to say what it is yet.”

Teigen has previously been open about choosing to have a baby girl — now-21-month-old Luna Simone — through in vitro fertilization the first time around. She had previously said “a little boy is next.”

She did confirm that the couple conceived through IVF again, though, explaining, “We did the harvesting — as they call it — again, where they make the embryos.”

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And with IVF, the star says there was no long wait before her pregnancy was confirmed — the couple knew just 11 days after treatment.

“You get the phone call and you’re like, ‘Please, please, please,’ and then you get the result and then you’re so excited,” she recalls. “It does make for a very long-feeling pregnancy because you know so early.”

“I think I randomly tweeted that you know those people where you’re like, ‘Oh, it feels like you’ve been pregnant forever,’ and you’re like, ‘Hey, screw you!’ I’m going to be that person,” Teigen says. “It feels long.”

The second-time mom-to-be says they’ve already started plotting baby names for their new addition, but admits picking the perfect moniker can be “tough.”

“We didn’t have Luna’s name until three days after she was born,” she shares, adding that they’re looking to her husband’s career for some inspiration.

“We love going the music route,” she says. “John loves looking at who he grew up with or people he grew up listening to. And maybe we’ll have a little baby Todd Smith, I don’t know. Maybe we’ll have a little Simone.”

“It’s hard,” Teigen laments. “We’re like, ‘Ella Fitzgerald, that’s such a pretty name!’ We go back and forth on everything but this isn’t our only baby so we’re going to divide up the names.”

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During her first pregnancy, Teigen shared the couple’s decision to have a girl exclusively with PEOPLE — something inspired heavily by her feelings about Legend, 39.

“I’ve made this decision. Not only am I having a girl, but I picked the girl from her little embryo,” she said at the time. “I picked her and was like, ‘Let’s put in the girl.’ ”

“I think I was most excited and allured by the fact that John would be the best father to a little girl. That excited me,” she explained. “It excited me to see … just the thought of seeing him with a little girl. I think he deserves a little girl. I think he deserves that bond.”

“A boy will come along,” she added. “We’ll get there too, so it’s not like we really have to pick. But he definitely is very lucky to have a little girl. And this girl is going to be so completely lucky to have John as her papa — it’s crazy!”

Lip Sync Battle LIVE: A Michael Jackson Celebration airs Thursday on Paramount Network.