Kourtney Kardashian and Travis Barker have legally tied the knot

Kourtney and Travis are still planning a "big wedding" in Italy "very soon".

A source confirmed to PEOPLE: "They had to legally get married first ahead of their big Italian wedding, which is happening very soon.

"All the details are set and the whole family, including all the kids, are very excited."

In photos and footage obtained by E! News, the newlyweds were seen driving away in a convertible with a 'Just Married' sign on the back.

According to a source, the 43-year-old reality star's grandmother, Mary Jo 'MJ' Campbell, was a witness.

Although the loved-up pair were thought to have tied the knot during a ceremony at the One Love Wedding Chapel in Las Vegas, the wedding wasn't legally binding because they did not obtain a marriage license.

Kourtney hasn't been married before, but she has Mason, 12, Penelope, nine, and Reign, seven, with ex-partner Scott Disick, While Travis has Landon, 18, and Alabama, 16, with second spouse Shanna Moakler.

It's the 46-year-old musician's third marriage, as he was also briefly married to first wife Melissa Kennedy between 2001 and 2002.

Meanwhile, Kris Jenner has been "sworn to secrecy" over the couple's wedding plans.

The 66-year-old star - whose eldest daughter got engaged to the

Blink-182 drummer in October 2021, after less than a year of dating - insisted she'll be "sitting in the background" and keeping tight-lipped to avoid getting into any "trouble" by spilling details before the big day.

She laughed: "I have been sworn to secrecy. If I say one thing about a wedding, I am gonna be in so much trouble!

"I am just gonna sit in the background. And not say a word because I don't want to get in trouble."