The president of the 47-nation UN Human Rights Council announced in a statement Monday that Alamuddin had been appointed on the commission, but the increasingly high-profile British-Lebanese lawyer later said she could not accept the role.

"I was contacted by the UN about this for the first time this morning," she said. "I am honored to have received the offer, but given existing commitments -- including eight ongoing cases -- unfortunately could not accept this role."

“I am horrified by the situation in the occupied Gaza Strip, particularly the civilian casualties that have been caused, and strongly believe that there should be an independent investigation and accountability for crimes that have been committed,” said the statement.

It wasn't immediately clear what caused the confusion or if someone else would replace her. Other members of the commission include Canada's William Schabas, an international law professor at Middlesex University, who will be the chair, and Doudou Diene of Senegal, a lawyer who has filled UN posts on racism and human rights in Ivory Coast.

Gabon Ambassador Baudelaire Ndong Ella, who presides over the UN's top human rights body in Geneva, said the commission would investigate all violations of international humanitarian and human rights law according to the council's July 23 resolution and report back in March 2015.

The Geneva-based advocacy group UN Watch called on Schabas to recuse himself from the commission because of prior statements critical of Israeli leaders.

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