Currie Graham and French Stewart

Currie Graham and French Stewart will play brother patients in the season premiere of Private Practice, TVGuide.com has learned exclusively.

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Graham (Raising the Bar) will play Russell, one of Charlotte and Sam's patients who needs a kidney transplant. Stewart (3rd Rock From the Sun) will play his estranged brother, Kevin, who is willing to give up a kidney.

However, once the docs meet Kevin, they realize he may not be fit to be a donor because of his mental state.

Season 4 of Private Practice premieres Thursday, Sept. 23 at 10/9c on ABC.