WASHINGTON — Hillary Rodham Clinton’s old band is getting back together.

Top donors to the supposedly arms-length Ready for Hillary PAC include a who’s-who of backers of her prior political efforts, amid increasing talk the group could function as a presidential-campaign-in-waiting.

Among them are Elizabeth Bagley, a top Democratic donor, who kicked in $5,000, and Joyce Aboussie, a big backer of Clinton’s failed 2008 campaign.

Claudine Bacher, a Key Largo, Fla., retiree who contributed $5,000 to the group in late June, previously gave to Friends of Hillary, HillPAC and Emily’s List. Sari Agatston, an exec at the South Beach Diet company, also gave $5,000.

Susie Tompkins Buell, a co-founder of the Esprit clothing line and a member of the group’s finance council, donated $5,000, and her self-named foundation kicked in $20,000.

Hillary’s network at first kept its distance from the outside group, which hopes to build a grass-roots network for her — but it’s pouring dollars in now. Pals contributing to the group’s $1 million haul include former top campaign adviser Harold Ickes, consultant Celinda Lake and former Bill Clinton Chief of Staff Mack McLarty.