David Tennant will be seen as the Purple Man in the upcoming Netflix series Jessica Jones (formerly AKA Jessica Jones). The Purple Man is a villain from Jessica's past, with links to Luke Cage. Jessica Jones will be released on Netflix on November 20, and will feature Mike Colter as Luke Cage in addition to Tennant's the Purple Man.
The Latino-Review reports that Tennant was recently spotted the set of Luke Cage, which is currently filming in New York City.
— Latino Review (@LRNews) September 29, 2015
No other details about the role have been confirmed, so it's unclear whether Tennant will appear in a flashback or if Luke Cage will be set before, during, or after the events of Jessica Jones. Previously released set photos indicate that Cage will already possess his superpowers in Jessica Jones, suggesting that Luke Cage will be set before or during those events.
While Tennant's appearance wasn't officially announced, it seems odd that he was so easily spotted. Photos seemingly confirming his appearance could spoil the ending to Jessica Jones, indicating that he manages to leave the series alive. It is worth pointing out that there is no context provided with the photos, so, as mentioned, Tennant could easily be filming a flashback, or a scene set before the events of Jessica Jones. It's also worth pointing out that the comic book version of the character does have a history of escaping prisons and coming back from the dead.
Tennant joins Rosario Dawson (reprising her role as Claire Temple), Alfre Woodard (Mariah Dillard), Frank Whaley (Detective Rafael Scarfe), and Simone Missick (Misty Knight) on the third Marvel Netflix series to be filmed. Luke Cage will begin airing in 2016. You can begin binge-watching Jessica Jones on November 20.