The movie adaptation of Downton Abbey is getting serious.

Imelda Staunton (Vera Drake, Harry Potter and the Order of the Phoenix) has joined the cast, the makers of the film told Deadline on Thursday.

Geraldine James, Simon Jones, David Haig, Tuppence Middleton, Kate Phillips and Stephen Campbell Moore are also on board with the Oscar-nominated Staunton. They join the original TV cast that includes Maggie Smith, Michelle Dockery and Hugh Bonneville, the entertainment news site said.

Downton Abbey, a hit period-drama series about the Crawleys and their servants on an English countryside estate, ran for six seasons on PBS and collected 15 Emmys. Talk of a feature film finally turned into an official announcement from producers in July that the movie was happening.

Production was expected to begin in September, according to previous reports.