Foo Fighters' frontman Dave Grohl (Getty)After Clint Eastwood's improvised empty-chair skit at last week's Republican National Convention, many people wondered if the Democrats would counter with some Hollywood firepower of their own.
It appears they will.
The actresses are expected to appear together following a performance by the Foo Fighters and before President Barack Obama addresses the convention.
The Los Angeles-based Foo Fighters performed at an Obama campaign fundraiser in February.
However, some of the surprise appearances may not be set in stone. According to Newsweek assistant culture editor Marlow Stern, a representative for Portman said the actress would not be attending the convention.
Wednesday's convention schedule has some celebrity flair, too. Olympic gold medalist Gabby Douglas will lead the Pledge of Allegiance before the evening session begins, the 16-year-old gymnast told Politico.
[Related: Voters still like Clint Eastwood]
Eastwood's appearance was preceded by rampant speculation after convention organizers released a revised schedule with an open slot before a speech by Florida Sen. Marco Rubio. Some speculated Sarah Palin or Rush Limbaugh would be the surprise guest, while others tabbed Tim Tebow, the devoutly Christian New York Jets quarterback. Former Presidents George W. Bush and George H.W. Bush were also floated as possibilities.
In an interview with USA Today, President Obama was asked if the Democrats would respond to Eastwood at their convention.
"I think we'll be playing this pretty straight," he said.
President Obama added: "I am a huge Clint Eastwood fan. He is a great actor, and an even better director. I think the last few movies that he's made have been terrific."