Kelly Clarkson has announced the sex of her second child on the way with husband Brandon Blackstock.

The first-season American Idol winner posted a photo of her 16-month-old daughter River Rose with the following caption: "In other news, River's gonna have a little baby brother :) #itsaboy We're so excited!"

Clarkson, 33, announced her pregnancy in late August while performing "Piece by Piece" at her concert at the Los Angeles Staples Center.

"I wasn't planning on announcing," Clarkson said before losing her composure and giggling. "I'm totally pregnant."

"My makeup artist is backstage hating me right now," the singer continued. "I just don't want you to think I'm on pills or drunk... I'd like to apologize to my husband. That was not planned. I just didn't want you to think I was crazy or something. Honestly, I'm just so hormonal today... I haven't vomited yet. That is a freakin' win, y'all."

On doctors' orders, Clarkson was forced to cancel the rest of her tour.

Back in February, Clarkson discussed how she'd love to have more children with Blackstock, 38.

"I want another one -- But I'm just a little frightened because [River is] so perfect," she admitted to People. "I feel like something horrible's gonna come out of me. Because she's so great -- like, the yin to her yang... But I won't put that out there. I'm gonna project happiness."

Clarkson and Blackstock wed in 2013 after getting engaged the year prior. She then became a stepmother to Savannah, 14, and Seth, 8, whom Blackstock had from a previous marriage.