By Zahra Khaliq The Princess of Wales has the King’s approval to steal the limelight from him, claims a royal expert – despite him growing increasingly jealous of Princess Diana for doing the same thing during their marriage. While reports previously surfacing on royal insiders’ fears that Prince William and Kate’s popularity will overshadow King Charles and Queen Camilla \- one expert claimed the monarch has given them his blessing to do so. Princess Diana’s overwhelming popularity was said to have put a huge strain on her marriage with Charles. The then prince was thought to have grown incre…