The current war of words kicked off when Cole spoke about Walsh's role as the girl group's manager, telling a magazine that he had had "zero involvement" in their career. Angered by the comments, Walsh responded that his "friendship" with the 'Promise This' star was "over".
Speaking to Heat magazine, the Irish music manager continued to criticise Cole, who he worked with on three series of The X Factor.
"What is she peddling this time? Eyelashes or hairspray? It's definitely not her music!" he said. "At least I am still on The X Factor and happy to be there. I'm a much better manager than she is a singer. She seems to be in the fashion business now, selling fake hair pieces, fake eyelashes, fake everything."
He continued: "Has anyone ever heard her sing live or a cappella? If she comes back on The X Factor, she needs to sing live this time. I don't know why she's started this war with me.
"I've always liked her - she's a very good looking girl, but obviously not the best singer in Girls Aloud. Nadine is - I always said that. Cheryl is a great clothes horse. Nice girl, but likes to get her own way."
In a final dig, Walsh added: "I've got two words to say: vocal lessons. When I write my book, I'll tell the real story of Cheryl."
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Watch the video for Cheryl Cole's 'Parachute' below: