She said: "I spoke to him last night and it is highly unlikely he will appear on Saturday's X Factor as he'll be in Ireland.
"I'm not sure about whether he will be on Sunday's show, it will depend on how he feels.
"But I can tell you, even though it's been a difficult week, he has been in constant touch with his bands."
Before the date of the funeral was announced, Cowell's sidekick Sinitta said she thought Walsh would be on the show as he did not want to let down his two remaining acts — John And Edward and Miss Frank.
"Very best friend": Walsh paid tribute to Gately
An X Factor spokesman said Walsh had been carrying on as normal as best he could under the circumstances, had chosen songs for his acts and was "very much in the loop" with their progress.
But they added that as the date of the funeral was only announced last night, no decision had yet been made on the format of Saturday's show.
Gately's family last night revealed that the singer's funeral would take place on Saturday at St Laurence O'Toole's Church in Dublin — a few hundred yards from where he grew up.
Meanwhile, a local paper in Majorca today reported that the 33-year-old had taken cannabis on the night he died but made no mention of other drugs in his body.
It said: "An analysis of the singer's urine indicates he had consumed cannabis. The relationship between this and his death will now have to be determined."
Autopsy reports yesterday confirmed Gately suffered an acute pulmonary oedema — or sudden build-up of fluid in the lungs — thought to have been caused by a heart attack.
