Wardrobe of the Old Gods

Don't despair if you like me didn't get the achievement when you collected the final piece.

The achievement didn't pop until after the "refund-timer" had run out and I vendored the item for gold.
Kinda weird since the item set showed complete in the collection section the second I bought the remaining item.

Part of Azeroth's Next Top Model.
Achievements for PvE-Appearences:

1. 
   
2. Tier 1: So Hot Right Now (Classic, [zone=2717])
3. 
   
4. Tier 2: Dress in Lairs (Classic, [zone=2677])
5. 
   
6. Tier 2.5: Accessor-Eyes (Classic, [zone=3428])
7. 
   
8. Tier 4: Outlandish Style (Bc, [zone=3457], [zone=3923] and [zone=3836])
9. 
   
10. Tier 5: Merely a Set (Bc, [zone=3607] and [zone=3845])
11. 
    
12. Tier 6: Black is the New Black (Bc, [zone=3959] and [zone=3606])
13. 
    
14. No Tier: Suns Out, Thori'dals Out (Bc, [zone=4075])
15. 
    
16. Tier 7: Undying Aesthetic (Northrend, [zone=3456])
17. 
    
18. Tier 8: Mogg-Saron (Northrend, [zone=4273])
19. 
    
20. Tier 9: Style of the Crusader (Northrend, [zone=4722])
21. 
    
22. Tier 10: Winter Catalog (Northrend, [zone=4812])
23. 
    
24. Tier 11: Glamour of Twilight (Cata, [zone=5334], [zone=5638] and [zone=5094])
25. 
    
26. Tier 12: Hot Couture (Cata, [zone=5723])
27. 
    
28. Tier 13: Wardrobe of the Old Gods (Cata, [zone=5892]) (You are here)
29. 
    
30. Tier 14: Sha of Fabulous (MoP, [zone=6297] and [zone=6067])
31. 
    
32. Tier 15: Thunderwear (MoP, [zone=6622])
33. 
    
34. Tier 16: Yaass'shaarj (MoP, [zone=6738])
35. 
    
36. Tier 17: Make it W-orc W-orc (Draenor, [zone=6967] and [zone=6996])
37. 
    
38. Tier 18: Extreme Makeover: Fel Edition (Draenor, [zone=7545])
39. 
    
40. Tier 19: That's So Last Millennium (Legion, [zone=8025])
41. 
    
42. No Set: Can I Get A Helya (Legion, [zone=8440], you want the Ensemble)
43. 
    
44. Tier 20: Retro Trend (Legion, [zone=8524])
45. 
    
46. Tier 21: Argussy Up (Legion, [zone=8638])
47. 
    

If you're impatient like me, put the item in Void Storage to "bind" it.