Pippa Middleton is reportedly engaged.

The party planner - who is the sister of Britain's Duchess Catherine, the wife of Prince William - was surprised by a "romantic and grand" proposal from boyfriend Nico Jackson during their vacation to the luxury Oberi Amarvilas resort in India earlier this month.

"It was exactly how he planned it. Very romantic and grand," a source said.

The couple - who have been dating for 15 months - have been celebrating their good news in private and are looking forward to a family Christmas before heading off on another trip, skiing in the Alps.

It was previously claimed that Pippa, 30, and Nico, 36, plan to marry in Scotland. "A wedding in London would never compare to her sister Kate's of course, and the prospect of erecting a marquee at her parents' house in Bucklebury for a party after the wedding service would be too low-key for her tastes these days," an insider said.

"There was some talk of Pippa hunting out suitable wedding venues on her next trip to Scotland. Nico loves the country too - he thinks it's beautiful - but when it comes to wedding planning he'll leave that to Pippa. He will go along with whatever she wants. And what she wants at the moment is a wedding in the Scottish Highlands. Nico would love a honeymoon in the Caribbean and a great bachelor party," the source added.

Pippa attracted the attention of the world when she was the maid of honor at the wedding of her sister Catherine - formerly known as Kate Middleton - to heir-to-the-throne William on April 29, 2011. Pippa wowed in a white figure-hugging dress - designed by Sarah Burton of Alexander McQueen.