The Private Lives of Pippa Lee

Keanu Reeves, Maggie Gyllenhaal, Alan Arkin and Monica Bellucci have joined the all-star cast of “The Private Lives of Pippa Lee,” from writer-director Rebecca Miller.

Adapted by Miller — the daughter of playwright Arthur Miller and wife of Daniel Day-Lewis — from her forthcoming novel, the comedy-drama “centers on a dutiful 50-year-old wife whose husband falls for a younger woman, freeing her to explore her buried sensuality and leading to a very quiet nervous breakdown.”

Robin Wright Penn already is on board as the title character. Julianne Moore and Winona Ryder have been cast as well.

Arkin plays the husband who leaves Wright Penn for Ryder. Bellucci will play his first wife.

Reeves will play Wright Penn’s younger lover, while Gyllenhaal plays Wright Penn’s diet-pill-addicted mother in flashback sequences. Moore portrays a lesbian novelist.

Reeves is now shooting “The Day the Earth Stood Still” for 20th Century Fox.