26. Duffy - age 29 - worth £6.18m
We haven't seen Welsh singer around Duffy for quite a while - her last album Endlessly came out in 2010. However, at the start of her career she reached international fame overnight with her hits 'Mercy' and 'Warwick Avenue'. She's still enjoying monetary success from those, it seems. She's currently thought to be working on her third studio album.