Chrissy Teigen and John CaldwellJohn Legend are paying tribute to their surrogate.

After the couple announced they welcomed a baby boy Wren Alexander Stephens surrogate, the Cravings author shared the meaning behind their son's middle name. In fact, it is a special nod to their "most incredible, loving, compassionate surrogate" Alexandra.

"We wanted to say thank you for this incredible gift you have given us, Alexandra," Chrissy wrote in an Instagram post June 28. "And we are so happy to tell the world he is here, with a name forever connected to you, Wren Alexander Stephens."

Chrissy and John welcomed Wren five months after she gave birth to daughter Esti. The couple's newest addition also joins siblings Luna, 7, and Miles, 5.

"For as long as I can remember, I've always wanted four children," Chrissy said in her post. "As a little girl, 2 glow worms and 2 cabbage patch dolls were perpetually in my arms, helping me stir in my kitchen, watching Alf with me. We'd sleep together nightly, each getting the same amount of kisses as to not make the others jealous."

She admitted that while she wasn't sure if she'd be able to carry another baby following her 2020 pregnancy loss, she and the "All of Me" singer decided to try one more time and she became pregnant with Esti.

"As we crept toward the safe zone of my own pregnancy," she continued, "we were overjoyed to learn Alexandra had become pregnant with a little boy."

And baby Wren joined the Stephens family on June 19. Chrissy ended her post by giving a nod to her and John's late son Jack, who died as a result of her 2020 pregnancy loss.

"Our hearts, and our home, are officially full," the 37-year-old wrote. "And to our Jack, we know both their angel kisses are from you."