Selena Gomez’s mom, Mandy Cornett (pictured above), gave birth to a baby girl on Thursday with husband Brian Teefey. This is the first sibling for the “Come & Get It” singer, whose parents divorced when she was younger, according to the New York Daily News.

On Mother’s Day, Gomez first revealed the big news: “Momma and Brian are finally letting me share the news…My mommy’s carrying my baby brother or sister 🙂 I’m the happiest girl in the world!”

Though a source told HollywoodLife that Gomez’s ex, the Biebs, contacted his former love to congratulate her on becoming a big sister, Selena’s best friend Demi Lovato was one of the first to publicly congratulate the “Spring Breakers” star.

“@selenagomez IS A BIG SISTER!!!!!! Everyone congratulate her and her family!!!!!! #CONGRATSSELENA!!!!” Lovato tweeted.

Of course, now that Gomez is sharing her mom with a little sister, everything will be different for a few years. The singer, however, doesn’t seem to mind as she told aufeminin.com before the baby’s birth that she wants to be the “best sister in the world.”

“There’s going to be a big age difference, so I think I’m going to be more like a cool aunt,” Selena also said.

In other Selena news, Gomez recently told HollywoodLife that she’s open to doing nude roles if it advances her career. According to the interview, Gomez is trying as hard as she can to “separate herself from her Disney past.”

What sort of impact will the 20-year age gap have on Selena’s relationship with her little sister? Do you think Gomez has been a good role model for her sister so far? Will the former “Wizards of Waverly Place” star be able to “separate herself from her Disney past?” Sound off in the comments section.