Beloved British actress Dame Maggie Smith has given a first-time director a big boost by signing on to lead the cast of his new film.

The Downton Abbey and Quartet star will join Kevin Kline and Jane Birkin in playwright and screenwriter Israel Horovitz's My Old Lady.

Smith will play the lover of a rich businessman who confronts his estranged son for the first time when he travels to Paris to liquidate an apartment he has inherited from his father.

Horovitz has adapted the screenplay from his own work and filming is scheduled to begin in Paris in September (13).

The first-time filmmaker says, "Of all my stage plays, My Old Lady is my very favourite. For years, this play has cried out to me to be seen in its Paris setting, to become a film... To create this film with Maggie Smith, Kevin Kline, Jane Birkin and Dominique Pinon is beyond thrilling."