MARK AND ARIZONA ARE THROWING CALLIE A BABY SHOWER, BUT HAVING TWO CO-HOSTS GETS COMPLICATED, ON ABC'S "GREY'S ANATOMY"

Loretta Devine ("Waiting to Exhale," "Boston Public"), Scott Foley ("Felicity," "Scream 3"), Peter MacNicol ("Ally McBeal") and Daniel Sunjata ("Rescue Me") Guest Star

"This Is How We Do It" - Richard is desperate for Derek and Meredith to accept Adele into their Alzheimer's trial, but will Adele stand in her own way? Meanwhile Mark and Arizona have conflicting ideas of the kind of baby shower Callie wants, Teddy is freaked out when Henry has another health complication -- leaving them both a little exposed -- and the competitiveness amongst the residents for the Chief Resident position is amplified when Richard receives the green light for his diabetes clinical trial, on "Grey's Anatomy," THURSDAY, MARCH 24 (9:00-10:01 p.m., ET) on the ABC Television Network.

"Grey's Anatomy" stars Ellen Pompeo as Meredith Grey, Patrick Dempsey as Derek Shepherd, Sandra Oh as Cristina Yang, Justin Chambers as Alex Karev, Chandra Wilson as Miranda Bailey, James Pickens, Jr. as Richard Webber, Sara Ramirez as Callie Torres, Eric Dane as Mark Sloan, Chyler Leigh as Lexie Grey, Kevin McKidd as Owen Hunt, Jessica Capshaw as Arizona Robbins, Kim Raver as Teddy Altman, Jesse Williams as Jackson Avery and Sarah Drew as April Kepner.

Guest cast includes Scott Foley as Henry, Rachael Taylor as Dr. Lucy Fields, Peter MacNicol as Dr. Stark, Loretta Devine as Adele, Daniel Sunjata as Eli, Marina Sirtis as Sonya, Pej Vahdat as Tarik, Colleen McDermott as Clara, Rick Peters as Sean, Denice Sealy as E.R. Nurse, Gordon James as Desk Nurse and Payton Silver as Dr. Knox.

"This Is How We Do It" was written by Peter Nowalk and directed by Ed Ornelas.

"Grey's Anatomy" is broadcasted in 720 Progressive (720P), ABC's selected HTV format, with 5.1-channel surround sound. A TV parental guideline will be assigned closer to airdate.

For more information on "Grey's Anatomy" please visit ABC.com.