Katie Holmes has put her husband Tom Cruise on a sex diet.

The 'Mission: Impossible' star is paranoid about gaining weight, so the Hollywood beauty has suggested spicing up their love life to keep the 47-year-old actor in shape.

A source said: "Tom had been complaining about how hard it is to keep off the pounds, so Katie vowed to help him out.

"Katie read somewhere that you burn up 600 calories just by having sex three to four times a week. So she's told Tom to think about how much they'd burn up if they put daily sex sessions on their schedule!"

Tom is thrilled with 30-year-old Katie's plan to increase their lovemaking and has promised to make it to every raunchy session.

The source added to America's OK! magazine: "Tom thinks the sex order is the best part of Katie's diet plan, and he's promised to up the bedroom romps whenever they are in the same town… just for the sake of his diet!"