Downton Abbey star Hugh Bonneville delighted his fans by sharing a never-before-seen photo from his childhood to mark his 57th birthday on Tuesday.The actor posted the throwback photo of himself sitting inside a toy car to Instagram, and it's so incredibly cute. Although the picture was taken decades ago, you could still clearly see it was him.MORE: Downton Abbey's Hugh Bonneville shares nostalgic snap of co-star Jessica Brown Findlay"Very touched by all the kind birthday messages today.