The British singer, who ranks ninth in the highest-paid celebrity list of Forbes, earning USD 80.5 million, shared the incident with her audience during her show at San Jose's SAP Center, reported People magazine.
"I went to H&M and my card got declined. Oh my days, pretty embarrassing. Nobody knew it was me, but I was mortified," Adele said.
During her US tour, the 28-year-old "Hello" hitmaker has been pictured at affordable retail stores such as H&M and Target.
The singer said that the first thing she does in California is to get an In N Out burger and go shopping at Target.