The first cast photos of British drama "Downton Abbey" season 4 has been revealed.

Meanwhile, a press event for the series 4 launch was held this week at the Mayfair Hotel in London for a sneak peak to one of the most successful shows in recent years.

However, not much of the three-part can be revealed yet, as journalists signed embargo forms to not release or tweet about it until Sept.12, according to the Telegraph.

ITV's British period drama series is set in the Yorkshire country estate of Downton Abbey, following the lives of the aristocratic Crawley family and their servants in the post-Edwardian era.

The series has been wildly popular since it premiered on ITV in UK in September 2010. The show is just as popular in the US, which premiered in January 2011 on PBS. It is the most watched series on both ITV and PBS.

Season 4 of the series is set to premiere in the UK next month, but the exact date has not been specified. Fans across the pond will have to wait until Jan. 5, 2014, for the upcoming season on PBS Masterpiece.

New cast members joining the show are Paul Giamatti, Tom Cullen, Nigel Harman, Dame Harriet Walter, Joanna David, Julian Ovenden, Dame Kiri Te Kanawa, and Gary Carr.

"Downton Abbey has seen many great characters visit the house over the years and we couldn't be more thrilled to welcome the new faces that will be joining the regular cast of Downton Abbey in Season 4," said executive producer Gareth Neame. "We hope audiences will be as excited about them as we are."