Philadelphia, US: Former US Secretary of State Condoleezza Rice abandoned international affairs for a Mozart piano concerto on Tuesday, teaming up with Soul legend Aretha Franklin to perform at a charity concert.

Rice, the Republican former aide to President George W. Bush, performed with the Queen of Soul, a committed Democrat who sang at President Barack Obama's inauguration, to raise money for underprivileged youth.

Rice is an accomplished pianist who considered becoming a professional musician before opting to specialize in studying the former Soviet Union.

She was greeted with cheers and a few boos when she appeared to play a movement of Mozart's Piano Concerto No. 20 in D minor with the Philadelphia Orchestra.

The first black woman to become Secretary of State, who justified the US-led war in Iraq with discredited claims that it harboured weapons of mass destruction, bowed and smiled briefly to the audience after her nine-minute performance.

The unlikely alliance of Rice and Franklin had its origins at a White House meeting between the two, after which Franklin suggested they join to raise money for a worthy cause, said Catherine Cahill, chief executive of Philadelphia's Mann Music Center for the Performing Arts, where the event was held.

Rice, now a political science professor at Stanford University, played a duet with Franklin on "Say a Little Prayer for You", which Franklin introduced by saying: "You didn't think she could play it, right?"

But the show really belonged to Franklin, who, dressed in a white satin gown, ran through classics including "Respect," "Chain of Fools", and "You Make Me Feel Like a Natural Woman."

The performance was expected to raise US$580,000 ($790,640) for an annual program that invites low-income children to attend concerts and master classes at the center.

"There's nothing political about this performance," Cahill said.