Justin Beckham, best known for penning the Jack Nicholson-Morgan Freeman drama The Bucket List for Rob Reiner, is lining up an equally impressive cast for his directorial debut.

Titled Gently Down the Stream, the film appears to be a family drama about a difficult romantic relationship between a young man and the sister of his adoptive brother. Is that even legal? Deadline is reporting on the cast as Beckham continues to fill out his roster, noting that Topher Grace has signed on to play the doctor who falls for his forbidden sibling. The story adds that Grace will be joined by Robert De Niro, Diane Keaton, Katherine Heigl and Amanda Seyfried.

That is a solid cast. And I’ve always appreciated Grace when he’s part of an ensemble, whether its broad comedy in the ’80s-set Take Me Home Tonight or trying more dramatic fare such as In Good Company. The funny thing about Grace, though, is that he’s also willing to think outside the box and take an action thriller like Predators or the forgettable Spider-Man 3. OK, so sometimes those choices backfire on him, but give him credit for refusing to play it safe every time. With that cast Stream is officially on our radar, and will stay there as we continue to gather news on the production as it begins shooting in Connecticut this July.