Gareth replied: "I'm not sure, but I don't think he looks anything like Simon Cowell."
Marsey Gordo said: "He's lost some weight!"
"Wow, he looks so different," user @engteachervng pointed out.
Although, viewer Gareth Blackwood complimented Simon's appearance, by tweeting: "Don’t know what skin products Simon Cowell uses but he’s looking great here. The Peter Pan of Pop."
The One Show airs weekdays at 7pm on BBC One.
