Due to chest infection Sir Tom Jones had pulled out and bronchitis and Will stepped in to take his place at the last minute.
He said: "I'm sad that Tom Jones can't do the show, I hope he gets well soon, and am very happy and excited to be playing Hyde Park for the Olympic events tomorrow".
He wrote: "Sadly I have contracted a chest infection w/bronchitis & due to doctors orders I've had 2 cancel tomorrows and Sundays show. Sorry to all x
"Thanks for all the lovely messages, I don't know if everyones understanding and support is making me feel better or worse! You're the best! (sic)"