The Queen actress told Redbook she doesn't have a beauty routine, and in fact, doesn't "really know what a beauty routine is."
Case in point: She cuts her own hair most of the time.
"I can't handle going to the hairdresser every six weeks, so I only go about once a year," Mirren said. "In between, I get out the scissors and do something, usually rather disastrously. Sometimes I'll even chop my hair the morning of a big red-carpet event."
"I have very fine hair, so I like a gentle shampoo and conditioner from either Crabtree & Evelyn or Kiehl's," she said.
Mirren's next film, The Hundred-foot Journey, is set to hit theaters in August.