The singer was performing 'Beautiful' live with Carly Rae Jepsen in Winnipeg, Canada as part of his 'Believe' world tour when the incident happened.
He can be seen walking along the set's balcony and then slipping at the top of the stairs, while Rae Jepsen attempts to help as he falls.
The incident follows Bieber's recent vomiting on stage during a show in the US, which he blamed on drinking too much milk before performing.
Bieber's new music video 'Beauty and a Beat - which features Nicki Minaj - broke the world record for the most views in 24 hours on VEVO last week after clocking up 10.6 million hits.
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