(my bb) Linus Roache and Geraldine Somerville are to head the cast of the epic TV dramatisation of the Titanic story being written by Julian Fellowes.
Downton Abbey creator Julian is scripting a series to be screened by ITV next year, coinciding with the 100th anniversary of the "unsinkable" ship's disastrous maiden voyage.
Linus, who has appeared in US series Law & Order and films such as Batman Begins, recently appeared in Coronation Street alongside his father William Roache (Ken Barlow).
Geraldine is known for her role as Harry Potter's mother Lily in the young wizard's adventure films, as well as appearing in BBC1's Survivors.
The cast for the four-part series also includes Celia Imrie, Toby Jones and Perdita Weeks.
The series begins filming in Hungary later this month, made by Bafta-winning producer Nigel Stafford Clark, whose successes have included Bleak House and Warriors.
Julian - who won an Oscar for his work on Gosford Park - will delve into the "unique perspectives" of the passengers on the celebrated ship which was holed by an iceberg in 1912.
James Cameron's 1997 film about the ill-fated voyage - starring Leonardo DiCaprio and Kate Winslet - imagined the lives of the ship's occupants and was one of the most successful movies of all time. It landed 11 Oscars including best director and best film.
The series is expected to be screened around the world.
Stafford Clark said: "There is a lasting fascination with the Titanic's one and only voyage, and never more so than in the year of its hundredth anniversary."