Avengers: Age of Ultron doesn't opens in the U.S. for a few more weeks (it arrives in other parts of the world first), but already die-hard Marvel fans are looking ahead to Phase 3 of the Marvel Cinematic Universe. One of the more anticipated superheroes debuting in Phase 3 is T'Challa or Black Panther (Chadwick Boseman), who shall first appear in 2016's Captain America: Civil War - something re-confirmed yesterday in Marvel's press release about the Russos directing Avengers: Infinity War - Part 1 & 2.
King T'Chaka - T'Challa's father and the Chieftain of Black Panther's home country of Wakanda - isn't expected to show up in the MCU until the Black Panther solo movie in 2018, but already casting rumors for the role are popping up. The actor in question is none other than Ghostbusters fan-favorite Ernie Hudson, who very recently played the ruler of a different fantasy kingdom - that of undersea-dwelling King Poseidon, on ABC's popular fairy tale blending TV series Once Upon a Time (see above).
El Mayimbe, taking a break from dropping rumors about the budding DC Cinematic Universe, is the source for this Black Panther rumor (see below). Mayimbe's write-up for Latino Review also mentions that his own sources have informed him that Hudson is hitting the gym and studying Black Panther comics, in order to demonstrate that he's prepared to play King T'Chaka on the big screen.
... But, of course, that is no way guarantees that Hudson will secure the role, especially so far ahead of the Black Panther solo film's release.