Former All White Tim Brown's footwear company has sold 1 million pairs of Allbirds shoes.
That means the merino wool shoes, worn by Prime Minister Jacinda Ardern during her fashion shoot for Vogue magazine, have flown off the shelves at almost a pair a minute since they went to market two years ago.
The San Franciso-based company also announced overnight that it was launching a range of shoes made from trees.
"Crafted from a textile that Allbirds engineered using eucalyptus pulp, our tree collection creates a cooling effect by wicking away moisture and, in concert with a silky-smooth mesh construction, delivers unmatched breathability and supreme comfort," the company said.
The latest range, which the company said is made from its "most sustainable material to-date" - is manufactured with eucalyptus fibres, which Allbirds said will require only 5 per cent of the water and a third of the land traditional footwear materials use.