Although Simon Cowell is patron of the children's charity Together For Short Lives, the music mogul was unable to attend his own fundraising event for the charity due to illness.
A spokesperson for Simon confirmed that he was bed-ridden with the flu, and so his partner Lauren Silverman attended the event in his place.
Lauren stepped in to host as Simon was too ill
A source told The Mirror: "He wouldn't miss this event unless he was feeling really ill, the charity means a great deal to him."
Lauren stepped up to play host at the Midsummer Ball event, and looked spectacular in a floor-length black gown, accessorising the glamorous look with a diamond bracelet and a black choker along with a black clutch bag to match.
The 38-year-old, who shares a two-year-old son with the X Factor judge, also wore her long brunette tresses pushed back, revealed a stunning pair of diamond earrings.
Simon was unable to attend as he was bed-ridden with the flu
Simon has spoken to HELLO! about his work with charity, as he is also vice-president for the Shooting Star Chase charity. Speaking at an event last week, he said: "I've never been very good with hospitals. Before I first went to visit one of the hospices, I had this idea in my head of a grey corridor of beds. But when I got there it was the exact opposite. It was very colourful, there's an amazing atmosphere and it feels like home."
He also spoke about how his work with the two charities has changed his perspective, especially after becoming a father. He said: "It definitely makes you more aware that they need help. You are just thankful that your child is healthy. It puts everything into perspective. You might think you've got problems, but you don't."