Kate Middleton

According to Us Weekly, the 35 year-old popped the question while on holiday with Pippa in India earlier this month. The couple stayed at the luxury Oberoi Amarvilas resort, according to the insider, with views overlooking the Taj Mahal.

Pretty romantic and the perfect place to pop the question!

"It was exactly how he planned it," one source said of the proposal, according to the site.

"Very romantic and grand!"

Wedding bells? Pippa Middleton and Nico Jackson have been at the centre of engagement rumours (WENN)

The couple, who have been dating for the last 15 months, have reportedly been celebrating the news in private, since their return from the romantic break. The claims come just a week after the MailOnline reported the same thing.

A friend confided to the Mail on Sunday: "Pippa and Nico made a pact to travel to lots of exotic destinations before walking down the aisle to start a family. There will be lots of trips like this in coming months."

According to the paper, insiders claim Nico has already told his family to "prepare for a spring wedding" and the couple are planning to make their special day perfect.

"Nico can't stop talking about it," said a pal of the 36-year-old Deutsche Bank stockbroker. "It's been the source of much excitement among his friends. He and Pippa want everything to be just perfect."

It's not the first time the couple have faced engagement rumours.

It was claimed Jackson was going to pop the question on the brunette's 30th birthday in September.

We spoke to Katie Nicholl, the author of Kate: The Future Queen about Pippa's marriage prospects.

Using her insider royal knowledge, she told EntertainmentWise: "There were rumours that they're secretly engaged. I'm told they're not yet, but an engagement is very likely on the cards.

"They're very close. Pippa's very much in love with him. You only need to see the body language between the two of them in pictures to see just how smitten they both are with each-other."

She went on: "Nico doesn't come from an artistocratic background, he doesn't have a double-barrelled name... [and] the people I've spoken to say hes really a very lovely man."

If Pippa does get married we wonder if big sister Kate will return the favour and take care of bridesmaids duties?

Pips virtually stole the show with her figure hugging cream bridesmaids dress at the royal wedding in 2011 and we reckon she'll be even more gorgeous on her wedding day, whether it's to become Mrs Jackson or not?

Is Nico in favour with the rest of the Middleton clan? He certainly is, according to Katie.

"I'm told that Carole particularly likes Nico, he's very welcome at their house... He's had the thumbs up."