The singer said he "couldn’t let the anniversary go by without marking it in some way"
The Hertfordshire festival is set to take place in July
Elsewhere, Formula 1 driver Lewis Hamilton and cinematographer Roger Deakins have been knighted
Other performers will include Joel Corry and MNEK, AJ Tracey and Clean Bandit
The rising actor plays an ex-pop star turned tabloid laughing stock in new sitcom 'Maxxx'
Other names on the bill include Stormzy, Kaiser Chiefs and Jess Glynne
The likes of Mystery Jets, Tim Burgess and Circa Waves will also play on the day
The R&B star's debut album 'Born To Do It' turns 20 this year