Pippa Middleton is set to the tie the knot in May.

Pippa Middleton

Pippa Middleton

The 33-year-old star - who is the younger sister of Duchess Catherine - is reportedly expected to marry fiancé James Matthews, 41, in six months, and the planning stage is well underway.

A friend of the bride-to-be told PEOPLE that the couple have earmarked May 2017 for their big day, adding: "Of course she is super excited and already planning everything.

"[They] have a lot in common - he's charming and old-fashioned. Everyone thinks he's quite the catch."

James presented Pippa with an engagement ring he had designed himself after popping the question in July, and the diamond sparkler is thought to be worth around $250,000.

The pal added: "He would never have bought something off-the-peg for her, it had to be very special."

Pippa recently admitted James is still trying to come to terms with being in the spotlight.

She said: "I have had a few years of being in the public eye and I have developed something of a thick skin. But managing it all on my own has been quite hard. I have quite a lot thrown at me, such as being followed by people hiding behind cars and jumping out with cameras. It can be unnerving.

"There's always something cropping up and has to be managed on my own. It's been a real eye-opener for James. There have been quite a few hurdles to negotiate."