Selena Gomez is going to become a big sister, Newsday's Frank Lovece reports. On Mother's Day, the singer-actress, 20, tweeted a photo of herself and her pregnant mother, Amanda Teefey, 37. "Hope all the amazing moms had a great day!" Gomez wrote: "I have the best momma in the world :)) I love you so much!" Gomez's mother -- a former actress who separated from husband Ricardo Gomez when Selena was 5 and married Brian Teefey in 2006 -- suffered a miscarriage in December 2011.