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 (left) is taking a cue from his left-leaning counterparts by hosting a fund-raiser 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 Sept. 6.

Tickets to the event start at $2,500 per person for entry to the general reception, $10,000 grants them access to the VIP photo reception and $25,000 saves them a spot at Duvall’s dinner party for the presidential hopeful’s wife and deep-pocketed supporters. Proceeds from the function will go to the joint fundraising committee Romney Victory, Inc.

A representative for Duvall said the actor wasn't reachable on Wednesday, as that was his first day filming his new movie.

Also read: Sarah Silverman Makes Not-So-Modest Proposal to Romney Supporter (Video)

By throwing in so publicly for Romney, Duvall bolsters his position among a relatively small group of Hollywood heavyweights, including Kelsey Grammer (pictured right), Jon Voight, Drew Carey and Adam Sandler, who register (at least with their checkbooks) on the conservative side of the political spectrum.

According to OpenSecrets.com, Voight donated $3,500 to John McCain’s campaign in 2008; Grammer contributed $4,600 to Rudy Giuliani and $2,300 to McCain during the last election cycle; Carey pitched in $2,300 for Ron Paul’s campaign in 2007 and Sandler ponied up $2,100 for Giuliani’s presidential run that same year.

The race to the White House is also heating up in Hollywood’s Democratic camp, with several celebrities – Maria Bello, Ian Somerhalder, Aisha Tyler and Pete Wentz among them — financially backing Obama’s bid for a second term.

August will be a busy month for Obama supporters like No Doubt singer Gwen Stefani, who is throwing a house party of her own in Beverly Hills on Aug. 12 featuring First Lady Michelle Obama. Power producer Harvey Weinstein and Vogue editor Anna Wintour are reportedly joining forces on Aug. 6 for their own high-end fund-raiser in Greenwich, Conn.

Also read: President Obama's Latest Campaign Co-Stars: 'The Wire' Cast Members, Nathan Lane, Harvey Weinstein

Meanwhile, cast members of “The Wire” are slated to meet pro-Obama donors at a private residence on Martha’s Vineyard on Aug. 15, and stage and screen star Nathan Lane will host an “East End for Obama” event, co-starring Vice President Joe Biden and actors Edie Falco and Julianne Moore, on Aug. 24.

Finally, George Clooney, who held a smashingly successful Obama fundraiser at Clooney's house in Studio City, Calif. on May 10, will stump for the president again in Geneva, Switzerland at two fundraising events for American expatriates on Aug. 27.