Natascha McElhone has joined Beau Willimon’s upcoming Hulu original drama series The First. McElhone joins the previously announced Sean Penn.

The UK’s Channel 4 and Hulu, commissioned The First and will co-finance it along with IMG and AG Studios, and have given the show a straight-to-series order. Willimon is creator and also serves as executive producer alongside his producing partner Jordan Tappis under their Westward Productions banner, which also own the series. IMG will handle sales in all territories.

The First centres on the first human mission to Mars and explores the challenges of taking the first steps toward interplanetary colonisation. Set in the near future, the story focuses not only on the astronauts, but also on their families and loved ones, as well as the ground team on Earth. Hulu has yet to release any details about the roles McElhone and Penn will be playing.

McElhone is currently starring as Alex Kirkman on Designated Survivor. Her television credits include seven seasons on the Showtime series Californication. Her film credits include The Truman Show, The Devil’s Own, Ronin and London Town.

“What I so admire about Natascha’s work is the fearlessness and honesty she brings to every role,” Willimon said. “She’s a wonderfully talented adventurer of the spirit, and I’m thrilled to be embarking on this journey with her.”

McElhone said: “I am so excited to work with original, maverick artists like Beau Willimon and Sean Penn - it’s a real privilege to be invited. As well as exploring Mars; I am thrilled to be accommodated by the brilliant planet Hulu and my favourite homegrown one of Channel 4.”

The series will go into production this year and is slated to premiere on Hulu and Channel 4 in 2018. Simon Maxwell, head of international drama, and Beth Willis, head of drama commissioned the series for Channel 4.

The First will premiere on Hulu in the US and on Channel 4 in the UK and Ireland.