Britain's Prince William is reportedly studying videos of how to change diapers in preparation for the birth of his first child in July.The prince and his wife Duchess Catherine are preparing for the arrival for their first child in July and William is determined to be a hands-on dad.A source said: "He's even been checking out nappy-checking videos on YouTube."His brother Prince Harry thinks it's hysterical and can't stop making fun of him but it's all good spirited."William is also keen to interact with his unborn child and tries to make time every day to sing to it.The source added to Now magazine: "He read somewhere it's never too early to start talking to your baby and he's taken the advice to heart even though it's not due until July."Kate thinks it's adorable. He's even been telling their bump some of the old stories his mother Princess Diana used to make up for him and Harry when they were kids."It's become an almost daily ritual for William to chat to her bump and sing a lullaby or song."