Two days after news broke that Jay Z was a father to twins, the rapper was spotted on Monday arriving at the Ronald Reagan UCLA Medical Center in Los Angeles.

The new father of three arrived wearing a simple white T-shirt and grey sweatpants with a white line running down the pant leg, as well as white sneakers.

Credit: INSTAR

A source confirmed to PEOPLE on Saturday that Beyoncé had given birth to twins, with her father, Mathew Knowles, confirming the news himself on Twitter.

Earlier in the day, Jay was spotted at a Soul Cycle class in Beverly Hills. “He joined the class just as it started,” a witness told PEOPLE. “He seemed very cheerful with lots of energy. He kept up with the class perfectly. He seemed to enjoy his workout. When she was pregnant, Beyoncé would come to class with Jay Z. Today, a friend joined him instead.”

“They’re here! #beyonce #twins #jayz #happybirthday,” he wrote, with a photo of balloons that were signed, “love, granddad.”

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The newest members of the Carter family join big sister Blue Ivy, 5.

The Lemonade songstress, 35, and her rapper husband made their double baby news public in February, with Beyoncé posting a stunning maternity photo to her Instagram account.

“We would like to share our love and happiness. We have been blessed two times over,” Beyoncé wrote alongside the snap, which showed her posing in a burgundy bra, sky blue panties and green veil amid a floral backdrop.

“We are incredibly grateful that our family will be growing by two, and we thank you for your well wishes. – The Carters,” the Grammy winner added.

Beyoncé celebrated becoming a second-time parent in late May, surrounded by family and friends — including mom Tina Knowles Lawson, La La Anthony, pregnant Serena Williams and Bey’s former Destiny’s Child bandmates Kelly Rowland and Michelle Williams — at a fun-filled “Carter Push Party.”

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Baring her baby bump, which was decorated in henna, Beyoncé danced with now-dad-of-three Jay Z while guests snapped photos and shared in the joy.

“She’s holding it down for so many other women that are with child and showing them, okay, still be as fierce as you feel and as you can because some women do have a hard time and don’t feel as great all the time,” Williams told reporters at April’s Inaugural Wearable Art Gala of her then-pregnant friend.