In today's 'making you feel old' news, it's been a whopping ten years since Lauren Conrad bid goodbye to Laguna Beach in favour of LA.

And yesterday the reality star-turned-author met up with two old friends in New York for a very special occasion – the launch of her new book, Celebrate.

Lauren's former co-stars Trey Philips and Dieter Schimtz were among the gang of friends and influencers who turned out to support her at the first press event for her party-planning guide, which is available to purchase from March 29.

MTV alum Trey was sure to post a snap of the trio – and their champagne glasses – on Instagram to commemorate the big evening.

"Congrats @laurenconrad on her new incredibly gorgeous and useful book. And a great party to boot!" wrote Trey who now works in New York with fashion designer Vera Wang.

Fellow Laguna Beach star Dieter also took to social media to congratulate his friend, saying he'd had a "blast" at the glam event.

And while she mightn't be on great terms with Kristen Cavallari these days, Lauren says she still fondly looks back on her Laguna Beach days as a "unique" time.

"There was an innocence to it because none of us were doing it to get any deals or other ventures — we were just all friends and it sounded cool so we did it," she says of the show's early days. 

"We didn't know what we were really doing, so I think it was this very interesting time where people didn't have ulterior motives. We were just filming a documentary."

We still have our fingers crossed for a Laguna Beach: Where Are They Now episode…