After over 300 aired episodes, "Grey's Anatomy" has become the second-longest-running medical drama. Many remarkable guest stars have walked the halls of Grey Sloan Memorial Hospital, some more unforgettable than others.
Some of these you may remember, but others will shock you! After releasing its 16th season, let's take a look at some of those faces.
1. Demi Lovato

2. Millie Bobby Brown

ABC
3. Mandy Moore

4. Abigail Breslin

ABC
5. Hilarie Burton

6. Scott Foley

7. Liza Weil

8. Dylan Minnette

ABC
9. William Daniels

ABC
10. Matthew Morrison

ABC
11. Bethany Joy Lenz

ABC
12. Josh Radnor

ABC
13. Alyssa Milano

ABC
14. Holly Marie Combs

ABC
15. Sarah Chalke

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