Big news for Doctor Who and Torchwood fans today, as Starz USA announced that the fourth series of Torchwood will launch its premiere episode on Friday, July 8, 2011 at 10pm ET/PT. Starz has also released some new poster artwork for the new series, which you can view here at right. Entitled Torchwood: Miracle Day, the series originally from the BBC, will feature the return of John Barrowman and Eve Myles who will be reprising their roles as Captain Jack Harkness and Gwen Cooper respectively.

New to the world of Torchwood are Mekhi Phifer, Bill Pullman, Lauren Ambrose, Alexa Havins, and Arlene Tur. Phifer is said to have a major role in Miracle Day, portraying Rex Matheson, a CIA agent investigating a global conspiracy behind what could be a serious threat to humanity.

The official announcement from Starz elaborates on the plot of Miracle Day:

The Torchwood news continues to trickle onto the web, with the announcement that Mekhi Phifer from the series Lie To Me, will be joining the cast of Torchwood: The New World. He will be set as a lead character to act opposite John Barrowman (Captain Jack Harkness) and Eve Myles (Gwen Cooper) in the upcoming fourth series.

Phifer will be playing a CIA agent named Rex Matheson, who Deadline points out is “a fast-tracked high-flyer with a lethal sense of humor who starts to feel his mortality when his life is put in danger.” It is unclear at this point whether he is allied with Torchwood or otherwise.

Torchwood: The New World is a joint venture between BBC and Starz USA that will see the series move out from its Cardiff, Wales, setting into a more international focus. Filming and production is said to include the UK, the United States, and Canada, under direction from showrunner Russell T. Davies.