The acclaimed actress, according to TVGuide.com, has joined the cast of "Private Practice," the spin-off of the popular ABC-TV program "Grey's Anatomy." McDonald has replaced Merrin Dungey in the role of Dr. Naomi Bennet. Bennet is the confidante to Dr. Montgomery, the character played by Kate Walsh.

The ABC-TV website also includes McDonald on its cast list: Kate Walsh (Addison), Paul Adelstein (Cooper), Amy Brenneman (Violet), Tim Daly (Pete), Taye Diggs (Jackson), Audra McDonald (Naomi) and Chris Lowell (Dell).

This intimate portrait of the choices and changes we make in our search for happy lives, reads the "Private Practice" description, "centers around neonatal surgeon Dr. Addison Forbes Montgomery of 'Grey's Anatomy.' After a failed attempt at reconciliation and two disastrous affairs, a move to Southern California to join her friends' health cooperative could be just the right prescription to jump-start Addison's own life."

A four-time Tony Award winner for her work in A Raisin in the Sun, Master Class, Carousel and Ragtime, Audra McDonald was also seen on Broadway in Henry IV and Marie Christine. The singer-actress made her solo Carnegie Hall concert debut in an evening of songs scored for big bands, performing several tunes from her Nonesuch CD "Happy Songs." McDonald's other solo recordings, "Way Back to Paradise" and "How Glory Goes," are also on the Nonesuch label. The acclaimed actress co-starred in the NBC series "Mister Sterling” and was recently seen in the WB series "Bedford Diaries." McDonald also made her Houston Grand Opera with a double bill of Send (who are you? I love you) and La Voix Humaine. McDonald was Tony-nominated for her work in the Roundabout Theatre Company's current production of 110 in the Shade.

"Private Practice" will air Wednesdays this fall at 9 PM ET. Visit http://abc.go.com for more details.