Sophia Bush is ready to get her scrubs back on. The actress, 42, will be joining Grey's Anatomy for the hit show's 21st season, PEOPLE confirms. Bush will play Dr. Cass Beckman, who is described ...

"Grey's Anatomy" Season 21 returns on Thursday, Sept. 26 at 10 p.m. on ABC. How to watch 'Grey's Anatomy' Season 21. The Season 21 premiere of "Grey's Anatomy" will air on ABC.