Troubled pop superstar Britney Spears is writing a letter of support to newly-single Prince William - according to media reports. The divorced singer, who split from husband Kevin Federline last year (06), sympathises with the British royal following his high-profile split with Kate Middleton last weekend (14Apr07). A source tells British newspaper The Daily Express, "She understands what it's like to have such a high-profile break-up. She has started writing him a note and is going to send it before the end of the week."