Clooney was already part of the $1 million sum kicked in by Not On Our Watch, along with Matt Damon, Brad Pitt, Don Cheadle and Jerry Weintraub.

If Clooney's generosity is contagious, other stars will step up to the plate as well as the phone banks when they align for tomorrow night's Hope for Haiti telethon, which is not only airing across most networks (including E!) but streaming live at E! Online.

In the meantime, other stars are encouraging involvement in the much-needed relief efforts:

• Mandy Moore, an ambassador for the global health organization PSI, blogged yesterday that she is "sickened and heartbroken by the thought of the tens of thousands who have lost their lives and the millions more who are without even the most basic necessities. In good times, the people of Haiti had little…now they have nothing." Just $6 buys a year of clean water for a family in need. Learn more about PSI and watch Mandy's video appeal here.

• Blink-182 is offering a special edition Haiti T-shirt available through their online store, with 100 percent of the proceeds from sales being donated to the Red Cross. Go here to buy one for $15.

• Tyler Perry has donated $250,000 to Haiti relief through his eponymous foundation. "If you are like me, I know you want to do something," he said. "If you are like me, I know you want to make sure that whatever you do, it actually gets to the people of Haiti." As a result, any donations made to the Tyler Perry Foundation will be added to the director's sum, with the guarantee that "100% of what you give will get to an organization that will use it to help the Haitian people." Go here to donate.

• Fresh off her Haiti-benefiting performance on The Oprah Winfrey Show this week, Rihanna announced she would be performing a new tune, "Stranded," during the Hope for Haiti telethon tomorrow night in London. She'll be joined on the track by Jay-Z, Bono and The Edge. Funds raised during the telethon will benefit a number of charitable organizations, including UNICEF, Oxfam America and Partners in Health.