Sharon, 60, who worked with Cowell on 'America's Got Talent', said his baby will learn singing first before the tot takes its baby steps, reported Daily telegraph.
"He will have that baby singing before it can walk. It'll be a star, she said.
Rocker Ozzy Osbourne's wife is very much looking forward to the tot's arrival and claims she is already planning outfits.
"I am knitting a bonnet and little booties as we speak," she said.
Sharon, who is grandmother to son Jack's one-year-old daughter Pearl, will be returning to the 53-year-old's 'X Factor' judging panel alongside Gary Barlow, Louis Walsh and Nicole Scherzinger this year.