Justin Bieber gave Ariana Grande and her fans a huge surprise on Saturday evening, when he joined the singer on stage to perform a duet of ‘Love Me Harder’. Grande is currently taking the US by storm on her Honeymoon Tour, which had rolled into Miami’s American Airlines arena.

Justin BieberBieber surprised Ariana Grande on stage in Miami

Bieber joined Grande for a rendition of the track, taking the parts originally performed by The Weeknd. But Justin wasn't quite as familiar with the single as he might have thought, and he ended up fluffing a few of the song's lyrics much to his embarrassment.

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"So I feel bad, I forgot the words Ariana," he told Grande after their rendition . "I've been trying to memorize them backstage for like an hour!" But Ariana didn't seem to mind too much, assuring poor Biebs that no one had heard.

The pair then when on to perform two songs including Bieber's hit ‘All That Matters’ and ‘As Long As You Love Me’, where Grande took over the rap verse originally performed by her boyfriend Big Sean.

After the concert Bieber tweeted, ‘Thank you @ArianaGrande and thank you Miami. I missed the stage. See u soon ;)’. The singer later shared a shot of himself and Grande performing on Instagram, with the caption, ‘Had fun with u Ariana, even tho I forgot all the words haha.’

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Ariana also seemed to have enjoyed her time on stage with the ‘Baby’ hit maker, later tweeting, ‘thank u miami babes and thank u @justinbieber!!!!!!’, after the show.

Watch Justin Bieber join Ariana Grande on stage in Miami