Simon Cowell's home in west London has been burgled while he and his family slept inside, according to reports.
The Sun said the 56-year-old's Holland Park property was entered during the early hours of Friday morning, with thieves taking cash and jewellery.
His girlfriend Lauren Silverman and son Eric were also home at the time, the paper added.
A representative from Syco, Simon's entertainment company, told Newsbeat they had nothing to add.
London's Metropolitan Police issued a statement in response to the story, confirming they had visited a house in the area.
"Police were called to an address in W14 on Friday 4 December at approximately 2:20am to reports of a burglary in progress," it said.
"Officers attended the scene but the suspects had left the area. Enquiries continue. No arrests."
It added that detectives from Kensington and Chelsea CID are investigating.
A spokesperson for The X Factor told Newsbeat that Simon attended rehearsals on Friday afternoon and did not foresee any issues with the weekend's semi-final live shows.
The Sun newspaper quotes a family friend as saying: "Obviously Simon and Lauren are really badly shaken by this. It's a horrible violation of their privacy."
Simon Cowell has had intruders in his home before.
In 2012, a woman was given a community order after admitting smashing a window at his property with a broken brick.
A court heard The X Factor boss was watching television in his bedroom when he heard a "loud bang" from his bathroom.
When police arrived they found Leanne Zaloumis hiding inside a walk-in wardrobe at the mansion.