Adele had to restart her Grammy Awards tribute to George Michael after messing up her vocals.

The 28-year-old singer was famously a big fan of the 'Careless Whisper' hitmaker - who was found dead at his home on Christmas Day (25.12.16) - and appeared incredibly nervous about honouring him with a rendition of his 1996 hit 'Fastlove' on stage at Los Angeles' Staples Center on Sunday (12.02.17), and stopped abruptly mid-song, swore, and asked producers if she could begin again.

Adele - whose 2016 Grammys performance of 'All I Ask' was plagued with technical difficulties - said: ''I know it's live TV. I f**ked up. I can't do it again like last year. I'm sorry for swearing. Can we please start it again? I'm sorry, I can't mess this up for him.''

After the performance, the 'Hello' singer - who donned a black crystal earring reminiscent of one which George used to wear - appeared on the verge of tears, despite the applause she received from the audience.

And Adele - who had also opened the show, at which she won five awards, with a rendition of 'Hello' - wasn't the only star plagued by technical difficulties on the night as Metallica's James Hetfield's microphone was turned off during the group's duet with Lady GaGa.

The guitarist could be seen singing to kick off their performance of 'Moth Into Flame', but no sound could be heard, prompting him to eventually share the 'Poker Face' hitmaker's mic to finish off the performance.

And at the end of the track - which had seen Gaga crowdsurf - James was clearly unhappy as he kicked down his mic stand and threw down his guitar.

The mishap came after actress Laverne Cox failed to even mention Metallica when she introduced the performance.

She said: ''We all begin somewhere. Great bands usually begin in someone's garage or basement or some empty warehouse.

''And if they're really good, part of them always stays there. Ladies and gentlemen, and all my gender-non binary peeps watching tonight, eight-time Grammy Award winners and six-time Grammy Award winner, Lady Gaga!''

Elsewhere during the ceremony, Bruno Mars and The Time gave a musical tribute to the late Prince, while Demi Lovato led a star-studded segment in honour of the 40th anniversary of 'Saturday Night Fever' by the Bee Gees alongside the likes of Little Big Town, Tori Kelly and Andra Day.