05/07/2011 07:40 am ET | Updated Jul 07, 2011

Laura Linney In 'Hyde Park On The Hudson': Star To Play FDR's Mistress Daisy

Franklin Roosevelt was perhaps the greatest American leader of the 20th century. Turns out the guy who's playing him isn't too bad, either.

Earlier in the week, Bill Murray was confirmed as playing the Great Depression and World War II-era President in the upcoming film "Hyde Park On The Hudson." Word was that Focus Features was using Murray's tentative agreement back in March to sell potential co-stars, and now just days after Murray's confirmation, a second cast member has agreed to join: Laura Linney, as Roosevelt's distant cousin Daisy.

The film will focus on both King George VI's visit to Roosevelt's residence away from the White House, as well as FDR's alleged affair with Daisy. A sixth cousin and close adviser, Daisy (real name: Margaret Suckley) was a Roosevelt Library archivist for many years, as she held close correspondence with the President and traveled with him often. She was even present when he died in 1945. Following her death in 1999, examination of her personal letters with Roosevelt led some to believe that they had had an affair.

Based on a British teleplay, the movie is supposed to be a drama, though Linney and, obviously, Murray, have impressive comedic chops.

Linney, who stars in Showtime's "The Big C," can be seen in Mark Ruffalo's new film, "Sympathy for Delicious."