Singer Selena Gomez made her name acting in children’s television shows. She was also singer Justin Bieber’s girlfriend for a while. But recently she is better known for her music. In fact, she has one of the top songs of the summer. Songwriter and DJ Kygo’s song “It Ain’t Me” features Gomez. It is ranked 20th on Billboard.com’s current summer music chart. You might think Gomez would have been singing at concerts around the world or appearing on television shows to talk about her music. But instead, she was preparing for a serious medical procedure. Gomez is the world’s most popular person on Instagram. She has over 125 million followers. On Thursday, she used Instagram to explain why she was “laying low” this summer. She posted a photo of herself in a hospital bed with her friend Francia Raisa. She said she needed a kidney transplant because of the disease lupus. Gomez received a kidney from her friend.