In September 2021, The Devil Wears Prada actor revealed he had been diagnosed with oropharyngeal cancer three years prior and had undergone chemotherapy and radiation to treat a tumour at the base of his tongue. During an interview with Willie Geist for the latest episode of Sunday Sitdown, Stanley detailed some of the side effects of the "brutal" treatments. "I lost 35 pounds (15 kilograms). I couldn't eat. I had a feeding tube for six months and everything tasted like you know what and smelled like you know what."