Prince William turned 37 this week and to celebrate, Kate Middleton surprised him with a homemade scrapbook.

The duchess enlisted the help of Prince George, Princess Charlotte and Prince Louis to fill it with family photos, paintings and drawings, a source has said. Kate kept the scrapbook at her sister Pippa's house to make sure her husband didn't find it. She wanted to give him something personal, the source said, to remind him about what's important in life. "Kate and the children have been compiling a large album of the children’s paintings, drawings and collages and prints. "They reflect what they have been doing over the past year. "You can look at any event they were involved with as a family and there will probably be a picture, drawing, print or photo. "It’s taken a great deal of time and effort to make, and as a present, it means something. "You could say it’s a reminder to William about what is really important. "It’s been put together with a great deal of care." Kensington Palace, William and Kate's home in London, shared a photo of the Prince on a trip to Tanzania to wish him a happy birthday. The snap shows him leaning in the window of a jeep with the desert in the background. Interestingly, there was no birthday post from @sussex_royal, Prince Harry and Meghan Markle's account. Instead, the account commented under the photo published by Kensington Palace, writing "Happy Birthday to The Duke of Cambridge!".