Presenter Greg James announced the 23 new additions on his Radio 1 Breakfast show, which also include Ellie Goulding, Rita Ora, Sigrid, Vampire Weekend and Billie Eilish.
This year the festival is taking place in Middlesbrough, after several cities including Coventry and Swansea hosted the "Biggest Weekend" in 2018.
Mumford & Sons said: "Last time we played Middlesbrough was February 2009, halfway through our snowball tour, so-called because all the bands and singers we played with along the way seemed to join us in the van for the next gig.
"That night, upstairs at Mohan's some hooligan sang 'boro football chants through the length of our set. A glorious and cherished memory. You have high standards to live up to, and although it's been 10 years we are thrilled to be back, this time hosted by the good people at Radio 1. See you there."
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