The 55-year-old took to Twitter to share a cute snap of him with Eric, one, who was sporting a similar look to Simon.
X Factor judge Simon joked: "No Eric. I said White shirt not t shirt."
Unsurprisingly Simon's followers were quick to gush over the snap, with one writing: "He's mini you!"
Another added: "Growing so quickly!!! Such a cutie!"
Earlier this year Simon opened up about fatherhood, admitting he's surprised at how 'easy' it's been.
He told E! News: "I love being a dad. It's been easy and I can't believe out's a year already. It's gone by, like, snap, but he's a fantastic little boy."
The music mogul confessed that he was initially nervous about having children, but watching Eric grow has helped him to overcome it.
Simon added: "I was always nervous about babies. I didn't know what to do with them. But actually, when you see someone day by day becoming, you know, more smart and doing different things and recognising you and now talking, I mean...it's an incredible feeling."