Singer last released an LP in 2013
The singer-songwriter is working on her follow-up to 2013's debut 'Pure Heroine'
Singer says she’s passionate about children having access to food
'Heartlines' is taken from their forthcoming album, 'Conscious'
Teen singer performed 'Life On Mars?' at last night's ceremony
BBC Radio 1 presenters Annie Mac and Nick Grimshaw are among those moved by her performance