Dominic West has joined the cast of the Downton Abbey sequel film.

The Affair star, 51, will join the popular costume drama franchise which previously launched actress Lily James, 32, to stardom.

Last year, the married West and James were photographed together in Rome kissing, being physically tactile and having a meal together.

The pair had been working together on the BBC's adaptation of Nancy Mitford’s novel The Pursuit Of Love, which is due to replace Line of Duty in the BBC One Sunday night slot when the current series of the crime drama ends.

After the photos were published, Dominic went on to speak to press with wife Catherine FitzGerald when returning to the UK and said: "I just want to say our marriage is strong and we are still very much still together."

Dominic West, pictured here with Lily James in 2018, is joining the sequel film to Downton Abbey
Dominic West, pictured here with Lily James in 2018, is joining the sequel film to Downton Abbey

The actor then handed over a similarly worded note to press, which was signed by both him and his wife, before kissing her in front of the cameras and turning to walk back inside their home.

It was reported earlier this month by Mail Online that Catherine had banned Dominic from "speaking to or working with" Lily again if they were to repair their marriage, with discussion of Dominic and Catherine renewing their wedding vows.

A friend of the couple has told the Mail on Sunday: "The idea of remarrying was talked about.

"Nothing was decided, or has been yet, but Catherine brought up the idea and it was much discussed. It shows how far things have come since those photographs."

Dominic West with wife Catherine FitzGerald after pictures emerged of him cavorting with Lily James while in Rome
Dominic West with wife Catherine FitzGerald after pictures emerged of him cavorting with Lily James while in Rome

It is unknown what role West will have in the upcoming Downton Abbey sequel film.

He will join the returning cast member s from the previous film along with fellow newcomers Hugh Dancy, Laura Haddock and Nathalie Baye.

Lily James previously played Lady Rose Aldridge on the Downton Abbey television series from 2012 to 2015, but did not appear in the 2019 film outing and is not expected to return for the sequel.

Downton Abbey 2 is in the works and will be released in December

Meanwhile, West is also reportedly joining the cast of Netflix royal drama The Crown for its fifth and sixth seasons, taking over from Josh O'Connor in the pivotal role of Charles, Prince of Wales.

He would be starring opposite Australian actress Elizabeth Debicki who is confirmed to be taking over the role of Charles' estranged wife Diana, Princess of Wales from actress Emma Corrin.

The Mirror has reached out to representatives of Dominic West and Catherine FitzGerald for additional comment on this story.

*The Downton Abbey sequel film will be released in December 2021.