The 23-year-old singer is set to become a father next year with stylist Briana Jungwirth and Cowell, who put the boy band together on "The X Factor", would be happy to be involved in the child's life, reported USA Today.
"If he asks, I'll do it in a heartbeat. I haven't formally been asked yet, but if he asks me it would be my pleasure."
Cowell's comments come after it was claimed that Tomlinson had already chosen Simon for the job.