Meghan Trainor Pregnant, Expecting Second Baby with Husband Daryl Sabara: 'I'm Crushing It'

The pop star also reveals her pregnancy book, Dear Future Mama, will come out in April

Meghan Trainor is going to be a mama of two!

The pop star is expecting her second baby with husband Daryl Sabara, she confirms to PEOPLE.

"What a blessing," Trainor, 29, tells PEOPLE exclusively. "I'm just so grateful I can get pregnant. And I'm like, 'I'm crushing it. This is amazing. This is my dreams.' I'm halfway there — I want four kids!"

The "All About That Bass" singer and the Spy Kids actor, 30, are already parents to son Riley, whom they welcomed in February 2021.

"We try to tell him, 'There's a baby in the belly,' but then he points to his belly now and is like, 'Baby.' And we're like, 'Oh no, it's not in yours — it's in Mama's belly!'" says Trainor, who also opened up about her happy news on the Today show Monday morning.

Courtesy of Meghan Trainor

Up until the reveal, Trainor kept her bump hidden by her favorite go-to garment.

"Hoodies, babe! I wrote a smash that says, 'Even with me hoodie on...'" the singer says, referencing her hit single "Made You Look." (She just dropped a remix of the song with Kim Petras last week.) "I only wear hoodies. And everyone's like, 'You're not even showing, you're so small.' I'm like, 'Well, you can't see me!' For real."

Now four months into her second pregnancy, Trainor says it's markedly different than her first.

Meghan Trainor, Daryl Sabara and son Riley. Meghan Trainor/Instagram

"It's like a real pregnancy. The first one was like make-believe. I had no symptoms with Riley to the point where I was like, 'We need to go to the doctor. There's nothing in me.' I got my symptoms late in my pregnancy with Riley," Trainor tells PEOPLE. "I got them a right away with this baby. I got red perioral dermatitis all over my face — so that's been fun with makeup — and popped early and was very nauseous. I was sick, my boobies were aching. This one was a ride. It was a rocky ride, but luckily it was during the holidays, so I could just chill and lay down. I pee every 20 minutes, and I'm fully out of breath just from talking. It's great."

This time around, she's also experiencing cravings for the first time — which are "everything and everything," she quips.

"I didn't feel extra hungry with Riley. This time I'm like, 'I need a pickle.' Even if I'm having chocolate or sweets, it needs to be followed with a pickle. It's weird, but it's great," Trainor adds. "I'll eat a whole meal, and then I'll be like, 'I could keep going.'"

'Dear Future Mama' by Meghan Trainor. Courtesy HarperCollins

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In addition to getting ready for baby No. 2, Trainor is also preparing for the release of her first book, Dear Future Mama, in which she'll open up about her experience with pregnancy, with weigh-in from her OB-GYN, registered dietician and personal trainer. The book will hit shelves on April 25.

"I'm an open book, and I love telling everybody everything about my grossness and all my truths," Trainor says to PEOPLE. "When someone goes, 'Oh my God, me too,' then it makes me feel like I'm not alone, and I'm like, 'I'm not weird, my body's not different. It's normal.'"