Elton was speaking on the first of BBC Radio 2's two-part 'John Lennon At 80' specials.
The hour-long 'John Lennon At 80' programs will be broadcast on October 3 and 4.
Urban also begins hosting a second series of The Keith Urban Playlist for national UK broadcaster BBC Radio 2 on August 8.
The show is the latest in the company's series of anniversary events, releases and more that have run throughout 2019.
The station will broadcast from Thursday 26 to Sunday 29 September from London’s iconic Abbey Road Studios,
With career album sales of ten million to his name, Cullum's new studio record represents a striking new direction.
Described as "old skool Westlife", the new track follows the Irish superstars' comeback single 'Hello My Love', released in January.
Knight will take the show across the UK with the Leo Green Orchestra to pay homage to one of the greatest songwriters of modern times.
Snow Patrol premiere their new single 'Don't Give Up' from 'Wildness', their long-awaited new album which will be released on 25 May.