The Portugal captain spent six years at Manchester United before moving to the Bernabeu for a record £80m in 2009.
While there have been reports that Ronaldo could return to Old Trafford, the 28-year-old has insisted that he is "happy" in Spain.
"I really miss English football," Ronaldo told Sky Sports News. "[United is] the club that's still in my heart and I really miss it, but now my life is in Spain. In the future we never know, but I'm really happy in the Spanish league."