The Superstar presenter dubbed the X Factor chief as the "God of Telly" in a message to promote Lord Andrew Lloyd Webber's contest for the titular role in Jesus Christ Superstar.
"Well,technically he is their Dad," she wrote. "God of Telly @itvsuperstar @JCSTheMusical ITV this Sat 8pm Sun 8pm."
The accompanying image shows Cowell in a long white gown, beaming as he stands over the heavens and the Earth.
Holden continued to joke with Superstar fans afterwards, tweeting a picture of a 'grown your own Jesus' novelty toy and saying: "If you don't help us by voting (from this Sunday) we may have to resort to this."
The actress recently said that she is "grateful" to Cowell for inviting her onto Britain's Got Talent and saving her career.