Rylan Clark has taken to Instagram to share a heart-warming throwback snap of him and his mum, Linda Clark, in honour of her birthday.The 35 year old TV star, who is known for his close bond with his mum, posted the photo with the sweet caption: "Happy birthday to my number 1. Happy Birthday mum x".The post was quickly filled with birthday wishes from Rylan's followers for Linda's 72nd birthday.The adorable photo shows a young Rylan, now towering at over 6FT 3IN barely reaching his mother's waist in his school uniform complete with a yellow and blue tie.