The 90210 star is backing the St. Bernard Project, which provides relief for survivors of the 2005 disaster, as the organisation aims to raise funds to build a wellbeing centre in the Louisiana city.
And she's hoping the charity will win the latest Pepsi Refresh Celebrity Challenge with the help of her Twitter followers.
In an online video, she says, "You should vote for us to win this $250,000 grant to help more people get back in their homes and to help with the building of the new mental wellness centre. I came to know about the St. Bernard Project because I made a trip down to New Orleans about two years after the storm hit.
"I was really devastated at my own ignorance to all the damage that still existed and I really knew I needed to give back. I saw an organisation that was family orientated that understood the needs (of people). They're one of the most efficient organisations I've seen and I'm so very proud to be part of the St. Bernard Project family and I really hope you can join the family - if for nothing else by clicking the button down there that says 'vote for us' and show us your support.
"We really need this money - the people of New Orleans need this money, especially in the aftermath of the BP oil spill. Please help us. Thank you so much."
The charitable actress has previously urged her fans to donate to The Blind Project, which helps former sex workers.