Hanks, Timberlake among ‘Stand Up to Cancer’ stars

Actress Marg Helgenberger, left, appears at the Stand Up To Cancer Day announcement at Los Angeles City Hall on Tuesday, Sept. 4, 2012. Councilmember Paul Koretz and the City of Los Angeles held the news conference to declare Friday, Sept. 7 as the official "Stand Up To Cancer Day" in Los Angeles. (Photo by John Shearer/Invision/AP)More A-listers have signed on to support the third Stand Up to Cancer telethon.