Harry Styles stunned fans when he emerged as a surprise guest during Steve Nicks’ emotional headline set at London’s BST Hyde Park. The ‘Water Melon’ singer, 30, joined the Fleetwood Mac veteran, 76, on stage during the city’s traditional summer festival on Friday (12.07.24) as she paid an emotional tribute to her late bandmate Christine McVie on what would have been her 81st birthday – as well as her late friend Tom Petty. Harry performed with Stevie as she sang her classic ‘Stop Draggin’ My Heart Around’ and Fleetwood Mac’s ‘Landslide’ before she paid tribute to her Christine, who passed awa…