This video posted on Youtube - and shot by Will Smith himself - shows school-girls in Lambeth going wild for their Hollywood visitor.
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The 20-year-old was stabbed after the party was gatecrashed after details were posted on social media.
Incident commander Andrew O'Loughlin said the fire was exceptional but it looked as though it had "possibly done its worst" when he arrived.
The ambulance arrived a minute after Weihong Yu gave birth in Camden.