Selena Gomez to become a big sister

Selena Gomez arrives at the 2011 American Music Awards on Nov. 20, 2011, in Los Angeles. Getty

(CBS) Selena Gomez has some baby news to share - and it has nothing to do with boyfriend Justin Bieber's paternity suit drama.

The actress/singer announced Friday that she is going to be a big sister.

Pictures: Celebrity baby bumps

Gomez, 19, posted a photo of her mother, Mandy Dawn Cornett, and stepfather and Brian Teefey on her Instagram account, along with a caption about her soon-to-be-sibling.

"Momma and Brian are finally letting me share the news," she wrote. "My mommys carrying my baby brother or sister :) I'm the happiest girl in the world!"

Cornett and Teefey married in 2006, according to People magazine. This will be their first child.

Selena Gomez's mother and stepfather in a photo posted on the singer's Instagram account. Personal photo