The Sunday Mirror says the pair had not had any contact since she filed for divorce on May 25 and vowed never to speak to him again - after he had cheated on her and sent lewd messages to a string of women.
But singer Cheryl, 26, decided to text the 29-year-old Chelsea and England left-back because she knows just how much playing in what could be his last World Cup means to him.
A source said: "It was a really thoughtful gesture. She didn't have to send it but thought it was only right to offer her best wishes.
"It was really sweet of her and shows that she's able to rise above the upset and be strong."
However, pals of Cheryl - who has been linked with hunky dancer Derek Hough, 24 - insisted her message did not mean she wanted to be friends with the footballer.
The source added: "That is a long, long way off at the moment."