Democratic mega-donor George Soros is backing a main super PAC dedicated to electing Hillary ClintonHillary Rodham Clinton19 companies that Trump has tweeted about Democrats wed themselves to abortion at their electoral peril Judd Apatow: Trump will run US like 'The Apprentice' MORE as president in 2016.

The super PAC, Ready for Hillary, tweeted on Thursday that Soros would serve as  one of the co-chairs of the group's national finance council.

Soros, a billionaire hedge-fund manager who has launched a number of liberal advocacy groups, has pledged $25,000 to the PAC, according to Reuters.

"His support for Ready for Hillary is an extension of his long-held belief in the power of grassroots organizing," Soros spokesman Michael Vachon told Reuters.

He previously contributed to President Obama's 2008 campaign, and during the 2012 cycle, gave $1 million to both liberal super PAC Priorities USA Action and American Bridge 21st Century.

Clinton hasn't yet made a decision on the race, but Ready for Hillary has been building a network of donors and supporters to help entice her to enter the race.

The group is focused largely on grassroots organizing, but it's drawn the support of a number of big-name Democrats as they jockey to come out as early backers of a Clinton presidential bid.