The site also reported that Garry Shandling will play Sen. Stern.
It's unclear how much Iron Man 2 screen time Oldman will have; he is also currently shooting the post-apocalyptic The Book of Eli, which is in the middle of production in Albuquerque, N.M., and in which he plays a major role.
The role of Howard Stark was previously rumored to be played by Tim Robbins. But that role is also rumored to be the one filled by Mad Men's John Slattery.
Iron Man 2 hits theaters on May 7, 2010.