But recently, he put work to one side to spend a month-long holiday with his fiancée Mezhgan Hussainy – and, as HELLO! magazine reports, it gave him the perfect opportunity to show off the results of a recent health-kick.
In this week's issue, number 1137, Simon's friends talk exclusively about his new exercise regime, revealing how the 50-year-old has been shaping up ahead of his big day.
And with Mezhgan, 37, on his arm as he cruises around the Mediterranean, the TV star couldn't look healthier or happier.
Also in this week's magazine we take a look at Simon's co-star Cheryl Cole, with a special report on the love she has found with Derek Hough.
Following confirmation of their relationship last week, HELLO! goes behind-the-scenes of their romance and looks ahead to what's in store for the 27-year-old beauty.
For these stories and more, pick up your copy of HELLO! magazine, on sale now.