The JLS singer, who won two Brit Awards with bandmates Aston Merrygold, Marvin Humes and Oritse Williams earlier this week, said that Keys is as talented as she is beautiful.
Gill told Bang Showbiz: "Alicia Keys is incredible. She has the whole package - amazing voice, incredible writing talents and she's such a good performer. She's cute too.
"She did a secret show in December and I was totally wowed by her. I am definitely going to see her live again later this year."