The O.C.'s Peter Gallagher Joins Season 18 of Grey's Anatomy

Peter Gallagher is joining Grey's Anatomy for season 18 in a recurring role as Dr. Alan Hamilton

Peter Gallagher Joins 'Grey's Anatomy' for Season 18, Character Details Revealed

Peter Gallagher's Daughter Reveals What It's Really Like to Have The O.C.'s Sandy Cohen as a Dad