She's going to be a big sister!

Selena Gomez took to her Twitter account Sunday to reveal her mother, Mandy, is expecting a child with her husband Brian.

"Hope all the amazing moms had a great day! I have the best momma in the world :)) I love you so much!" she captioned the above snapshot, which shows the pop star cradling her mom's baby bump.

Mandy, who gave birth to Selena when she was just a teenager, suffered a miscarriage two years ago.

In other Selena news, the brunette beauty revealed she is no longer with Justin Bieber and is "absolutely available in every way" during a Boston Kiss 108 interview last Friday.

That's news to us! Last time we saw the pair, they were snuggling in sappy Twitpics!