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
Late icon receives special posthumous honour at London ceremony
The pair were pictured together, along with actress Tilda Swinton, in 2014
The 'Royals' singer took to Twitter to put down accusations
Pop star joins fans for an impromptu Tumblr Q&A
'Team Ball Player Thing' released in aid of Batten disease, a rare recessive neurodegenerative disorder
The Australian electronic producer was performing at the Los Angeles festival on Sunday night (August 23)
The live collaboration took place at Nationals Park in Washington DC on Monday (July 13)
Singer-songwriter previously teamed up with the UK duo at the 2014 Brit Awards