Two top donors to President Obama's super-PAC are now helping out one that supports Hillary Clinton for president.

Steve and Amber Mostyn have signed on as founding members of Ready for Hillary's national finance council. The two combined to donate more than $5 million to Democrats in the last election, including $3 million to the pro-Obama Priorities USA.

The Mostyns are top Texas-based trial lawyers. Joining them on the group's finance council is Susie Tompkins Buell, the co-founder of the Esprit clothing company. The longtime Democratic activist is a friend of Hillary Clinton's who served as her San Francisco fundraising chairwoman in 2008.