The supermodel - who will tie the knot with The Kills guitarist in Oxfordshire, South East England, on July 2 - has lined up celebrity chef Heston Blumenthal's latest London restaurant Dinner as the venue for their families to get to know each other better before the big day.
A source told the Daily Mirror newspaper: "She and Jamie don't want anything to go wrong on the day and they thought this would help break the ice and make everyone a lot more easygoing."
The guest list for the meal includes Kate's ex-boyfriend Jefferson Hack, her mother Linda and father Peter - who divorced when Kate was still at school - as well as Jamie's dad William, mum Carole and older sister Sarah.
And the 37-year-old catwalk star - who was originally going to fly her guests to Paris for a meal at the Ritz, but had to change her plans after some guests couldn't make it - is hoping there is no "awkwardness" between her and 42-year-old Jamie's families.
The insider added: "Kate wants it to be light-hearted and not a 'Meet The Fockers'-style grilling from either side.
"It's the bringing together of two families so it's a big deal for her. Kate wants them to all get merry, eat fantastic food and just relax with each other before the wedding day and the party. She doesn't want any awkwardness on the day."