It's a girl!

Ashlee Simpson and husband Evan Ross welcomed a baby girl Thursday night, according to E! News. This is the couple's first child together, while Simpson is already the mother of 6-year-old boy Bronx from her past relationship with rocker Pete Wentz.

"Their whole family was around to support them," a source revealed. "Evan was very emotional and loves Ashlee so much. He did not leave her side and wanted to go through this with her every step of the way. He can't wait to be a dad. He would do anything for Ashlee and now this baby girl. Ashlee is doing great and can't wait to get home to be with her family."

No mention on what the couple named their bundle of joy.

Simpson, 30, and Ross, 26, began dating in 2013 and tied the knot at his mom Diana Ross' Greenwich, Conn., estate last August. The celeb-filled wedding included the singer's older sister, Jessica, brother-in-law Eric Johnson and the couple's two children - daughter Maxwell Drew, 3, and son Ace Knute, 22 months - who served as flower girl and ring bearer.

Ross began posting a series of photos from the couple's nuptials earlier this week, including intimate shoots of the couple holding hands and kissing. He also posted a photo of the couple's wedding reception and rehearsal dinner.

 Love those lips!!! #wedding memories

A photo posted by Evan Ross (@realevanross) on Jul 27, 2015 at 5:53pm PDT

The couple announced they were expecting a baby together in December and later revealed that they were having a girl.

"I told him pretty early on," Simpson told Us Weekly about telling her son of her pregnancy. "He wanted to have a sister, so he's really excited! He's got a little brother. Now he's going to have a little sister!"