Olly, who finished as runner up on the show in 2009, performed his number one hit single Heart Skips A Beat at the ITV1 awards ceremony.
The track, which lost out to fellow X Factor stars One Direction in the Best British Single category, features British rapping duo Rizzle Kicks.
Dappy, who is currently at the top of the charts with his new song Rockstar, moaned about Olly's performance this week: “Bloomin hell. Olly Murs needs to learn how to sing, boy.
"He came off ‘The X Factor’ so he should be able to sing and yet that was a horrific performance. You can’t do things like that”.
Watch Olly's performance at the BRITs below and tell us whether you agree with Dappy's take on it!