LOS ANGELES (TheWrap.com) – Robert Duvall is an unusual figure in the Hollywood milieu – he’s a well-known entertainer who is willing to lend his star power to promoting a Republican politician. The “Apocalypse Now” star is taking a cue from his left-leaning counterparts by hosting a fundraiser for presumptive GOP presidential candidate Mitt Romney next month. According to an invitation spotted by National Journal, Duvall is opening his Middleburg, Va., home to Romney boosters – as long as they’re willing to open their wallets – and “special guest” Ann Romney on September 6. …