London: English singer Mick Jagger says he "can't function" in jeans. The Rolling Stones frontman can't understand how his bandmates used to feel comfortable under hot stage lights in denim trousers and also rejected leather garments because he found both materials too restrictive, reports femalefirst.co.uk. “Keith (Richards) and everyone would always wear jeans. I can't imagine how you could function in jeans. There's no give in them,” Jagger told MOJO magazine. “Now, people still manage to do a lot of amazing stuff wearing jeans. But for me, it wasn't a great feel," he said, while adding that he "never used to wear leather." For the 72-year-old, comfort and practicality is essential on stage. “Comfortable is a big thing if you're on stage. I used to wear these moccasin shoes -- bought them somewhere in California,” he said.