About that peculiar age difference: Variety reports that Oscar winner Forest Whitaker is in talks to play Allen; Oyelowo would play Allen's son. Suddenly, it all makes sense.
No word yet on any official co-stars, but there are plenty of major players lining up for some historical significant roles. THR reported that Mila Kunis and John Cusack were in discussions to play Jackie Kennedy and Richard M. Nixon (!), while Hugh Jackman could play anyone from Dwight D. Eisenhower to John F. Kennedy.
Allen's story was first detailed by the Washington Post in the days after Barack Obama was elected as the nation's first black president. Per Variety, "The Butler" would be a little bit like Steven Spielberg's "Lincoln," a film with a sprawling cast of actors and one towering lead performance (Daniel Day-Lewis as Lincoln; Whitaker as Allen).
Whitaker won an Academy Award in 2007 for his portrayal of Idi Amin in "The Last King of Scotland." Since then, however, he's been relegated to small roles and television work. Whether "The Butler" marks his return to glory -- and whether Daniels can pull together what would be an A-list cast -- remains to be seen.