Try as he may, Irish music manager Louis Walsh can't shut up Susan Boyle defender Simon Cowell!

Simon Cowell, Susan Boyle's chief protector, has mocked top Irish music promoter Louis Walsh for being biased towards Irish acts on Cowell’s music competition show “The X Factor.”

Walsh, former manager of Irish boybands Boyzone and Westlife, recently spoke out against Cowell’s prodigy, Susan Boyle, predicting the Scottish singing star will “collapse” under the pressure of the music, which perhaps has spurred Cowell to hit back at the Irishman.

The British music mogul made fun of Walsh, a fellow judge on “The X Factor,” for always showing prejudice to Irish contestants.

Cowell bickered with Walsh after a Dublin born duo performed the Backstreet Boys hit “I Want It That Way,” saying that even though they were the “most irritating contestants” he had seen in a while, Walsh would of course vote “yes” for the pair to go through to the next round.

When the Dubliners revealed their hometown before they even sang, Cowell laughed: “Well, it’s a yes from Louis then!”

Cowell later took another dig at Walsh, saying the Irish music man only likes male performers with “blonde hair, wearing a blazer and singing ‘You Raise Me Up,’” referring to the many Irish acts, including Westlife and Celtic Thunder, who have performed the song.

Walsh was criticized back in 2005 for his Irish bias, with Sharon Osbourne accusing him of voting with his passport rather than on talent.