Earth Hour: Miranda Kerr on track to broadcast free yoga class

Miranda Kerr shows off lingerie at the Victoria's Secret Fashion Show.

Miranda Kerr will host a free yoga class if at least 500 people take up her challenge as part of the upcoming Earth Hour event.

The Australian supermodel, who took to the runway in the $2.5 million bra Fantasy Bra at last year's Victoria's Secret fashion show, posted her appeal on You Tube in a bid to raise awareness of the annual energy saving event. Watch it here: http://youtu.be/_xInYUUOyBg.

The global event organized by WWF (World Wildlife Fund) began in Sydney in 2007 and encourages individuals, businesses and governments to turn out their lights for one hour in a bid to raise awareness of environmental issues.

For this year the event has encouraged participants to make "I will if you will" dares and ahead of the March 31 switch off. Kerr encouraged her fans to participate, explaining,"I will conduct a free yoga class if 500 people upload their own 'I will if you will' challenge toyoutube.com/earthhour."

Although the model doesn't specify where the class will take place, it will most likely be on You Tube, and so far Kerr looks set to hit her goal -- over 150 pledges have already been made.

Visit www.youtube.com/earthhour to accept her challenge.