Also up for grabs are exclusive ticket bundles to see 5 Seconds Of Summer and Hans Zimmer live during 2021.
This year's event was due to host stars including Sam Fender, Rage Against The Machine, Liam Gallagher and Dermot Kennedy.
In a poll of 20,000 listeners, the legendary song beat off strong challenges by Oasis, The Stone Roses, David Bowie and more.
The young singer-songwriter's performance kicks off at 8pm GMT tonight, 1 April.
Fender said: “‘That song is such a long-standing favourite of mine, and Amy remains a national treasure."
This year's line-up also includes The Strokes, Michael Kiwanuka, Suede and Bon Iver.
The new song is a stand-along track which doesn't feature on Fender's chart-topping 'Hypersonic Missiles' album.
Stormzy, Liam Gallagher and Rage Against The Machine have also been confirmed as this year's headlining acts.
Ever since The Beatles invaded America, the UK has been exporting top tier talent from across the pond. Here are 10 of the best UK musicians poised to break stateside.
The events, also featuring Louis Tomlinson, Sigrid and more run at intimate venues across London from 8 to 22 February.
The winners will be revealed next month at the annual awards ceremony, which is due to take place at London’s The O2 on 18 February.
Taylor Swift, The Killers, Billie Eilish, Twenty One Pilots, Pixies, Alt-J and Tove-Lo and Foals have already been announced for the Madrid-based event.
The iconic UK festival will return once between 11 and 14 June, with the above acts topping the bill across the entire weekend.
‘Saturday’, also features on the young singer-songwriter's much-acclaimed debut album 'Hypersonic Missiles'.
Special guests on the Nevadan band's UK and Irish dates include Sam Fender and Manic Street Preachers.