The 37-year-old musician, who is planning about the collaboration for quite a some time, said it will be a blast when it happens, reported Daily Star.
"Rihanna and Cheryl will be great when it happens. I first told Rihanna about Cheryl in 2009 when I said she's like the princess of England.
"No disrespect to the real royals but Cheryl's the pop princess and I've been telling Rihanna, so hopefully it will happen soon," he said.
