The 26-year-old singer posted on her blog late Wednesday that she had hip surgery and it "happened so fast." She canceled her "Born This Way Ball" tour last week.
She thanked her fans in the post, saying they gave her "a lot of strength." Lady Gaga said that as she was wheeled to surgery, she reflected on her fans. She wrote: "Sometimes you are so brave that it terrifies me. I wonder how it's even possible."
Lady Gaga canceled more than 20 dates on the remainder of her tour, which began last April. She originally postponed four dates last week after experiencing difficulties during her concert in Montreal. She explained to fans on Twitter that she'd hurt herself while performing some time ago.