The singer – who separated from husband Ashley Cole in February amid claims he cheated on her – has grown increasingly close to the dancer, who she worked with on her 'Parachute' video, and Derek's family say the British beauty is the "girl of his dreams".
His stepfather, Aaron Nelson, said: "For Derek, this is true love. There is no doubt about it. He is totally in love with her. And it's easy to see why. She is one hell of a girl. Very talented and incredibly beautiful.
"I know Derek is in love with her because he has told me he is in love with her and I think she feels the same way about him. She is the girl of his dreams and he is desperate to be with her. He would follow her to the ends of the Earth."
Aaron also laughed off speculation that Derek is gay, insisting he is ready to "settle down" with Cheryl – who has also been romantically linked to Black Eyed Peas star will.i.am – after the pair jet off on a romantic break together.
He added to the Sunday Mirror newspaper: "People think he is gay because he is a dancer, but that boy is about as far from being gay as you can get. He is a stud. Women go crazy for him.
"Derek is in London at the start of a five-week break. But he won't be spending all his time there. He and his new lady are going off on a romantic holiday. I can't say where as he'd kill me.
"He does not want the paparazzi following him there. But it's somewhere very nice. After that, who knows what is going to happen? But this girl is very special to Derek and he is at a point in his life where he is ready to settle down. He is ready to be in love and make that commitment."