Simon was left shaken after his home in Holland Park, west London was broken into during the early hours of Friday (4 December) morning, with thieves stealing jewellery and cash.
It has now emerged that the guard didn’t know anything about the robbery, as he was on the toilet at the time - an excuse Simon is seemingly unimpressed with, as The Sun has claimed he will hand him his P45.
The Mirror reported that it was another security guard, M'batonha Mendes, who ended up chasing the robber down the street, while he was working on another job.
When he alerted Simon’s security team, M'batonha was surprised to learn they had no idea about the break-in.
Speaking about how he caught the burglar, Mendes said: "I noticed that as he was walking, something dropped behind him. I got out of the car and picked it up. It was a passport with Simon Cowell’s picture.
"I was completely shocked. I jumped in my car and drove after him. I knew whatever was in that bag was valuable. After I grabbed it off him, I called the police, then my supervisor. I went to Mr Cowell’s house and waited there."
Simon revealed that he feared for his son’s safety after the burglary, and was thankful no-one was hurt.
"That was the first thing we did, to make sure he was OK,” he told The Sun.
He later took to Twitter, thanking fans for all their tweets following the break-in.
“Thanks for all of the messages. Nobody got hurt. I don't think I have the best guard dogs in the World,” he joked.