Rewind·Posted on Jan 28, 201826 Celebs That Prove Just About EVERYONE Has Been On "ER"Long before he was Ron Swanson, Nick Offerman was Rog.by by Christopher HudspethBuzzFeed Staff, by Crystal RoBuzzFeed StaffLinkFacebookPinterestTwitterMail 1. Zac Efron 2. Ariel Winter 3. Shia LaBeouf 4. Eva Mendes 5. Josh Radnor 6. Chris Pine 7. Rooney Mara 8. Gabrielle Union 9. Chadwick Boseman 10. Lucy Liu 11. Ewan McGregor 12. Josh Hutcherson 13. Adam Scott 14. Kirsten Dunst 15. Nick Offerman 16. Kat Dennings 17. Kristin Davis 18. Tobin Bell 19. Cara Buono 20. John Hawkes 21. Deborah Ann Woll 22. Stana Katic 23. Michael Cudlitz 24. Eric Stonestreet 25. Josh Peck 26. Aaron Paul