The 55-year-old music mogul attended the Katie Piper Foundation Ball in London and took girlfriend Lauren Silverman along too.
As the happy couple arrived at Lindley Hall, 37-year-old Lauren wowed in a bright green one-shouldered gown.
The Roland Mouret dress looked incredible on Lauren's slender figure and cost £1995.
The mother-of-two teamed the standout garment with a pair of strappy metallic heels and statement earrings.
Simon also made an effort for the occasion and wore a black suit with a white shirt and his trademark spectacles.
The pair made sure they posed for pictures before heading inside and joining Simon's fellow X Fcator judges, Cheryl Fernandez-Versini and Melanie Brown.
As they left the ball, Lauren was seen clutching a huge bouquet of flowers and held Simon's hand as they headed home to baby Eric.
Simon didn't waste any time in taking to his Twitter account, and posted: "Had an amazing night with @KatiePiper at her fundraising ball. An incredible person."
Mother-of-one Katie also tweeted, and wrote: "Thank you 2 everyone who attended, supported and donated last night @KPFoundation Ball. You were incredible, thank u 4 helping us hit target."
The 31-year-old looked stunning as she arrived at her own event wearing a black floor-length gown and bright red lipstick.