Sharing a photo of himself dressed in character as he filmed the brand new fourth series yesterday, Jeremy said: "Harry is back at it... #MrSelfridge."
Jeremy was filming with former Coronation Street star Katherine Kelly and new cast member Sacha Dhawan.
Mr Selfridge follows the real-life story of charismatic American retail entrepreneur, Harry Gordon Selfridge, and his famous Selfridges department store along London's Oxford Street.
Most of the drama is filmed in London, but Jeremy, Katherine and Sacha headed to France to film some additional scenes.
Katherine also shared a photo of herself posing in front of a private plane, which was all thanks to Hollywood star Jeremy!
She tweeted: "Back from filming in style thanks to the legend that is @jeremypiven #mrselfridge @Sacha_Dhawan."
Katherine has reprised her role as Lady Mae Loxley for the fourth series. She was absent from the third series because she was on maternity leave when filming began.
The fourth series will focus on Harry's dramatic fall as he loses hold of the empire and social status that he worked so hard to create.
However, there could be sad news in store for Mr Selfridge fans, as Amanda Abbington, who plays Miss Mardle in the drama, revealed that the fourth series will be the last ever one.
She told What's On TV in April: "It's the last series, so after this we won't be doing any more, which will be really sad because it's been a part of my life for four years."
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