They join headliners Bon Iver, The National and The Cure, plus acts including Vampire Weekend, The 1975, Smashing Pumpkins, Jorja Smith and Mogwai.
The full list of new additions is as follows.
Years & Years, The Chemical Brothers, Robyn, Iggy Pop, Disclosure (DJ set), H.E.R., Tokimonsta, Nao, Charlotte De Witte, Jasss, Vince Staples, Sharon Van Etten, Eric Prydz, George Fitzgerald, Haai, Valeras, Miles Kane, Mitú, Yonaka, Le Butcherettes, Delaporte, Lala Lala and Doblecapa.
Mad Cool Festival 2019 takes place in Madrid between 11th and 13th July 2019. Tickets are on sale now.