Pippa Middleton Wedding News: Meghan Markle Arrives in the UK For the Celebration.

Reuters/Toby MelvilleThe Duchess of Cambridge's younger sister, Pippa MIddleton, is set to tie the knot with her fiancé James Matthew on May 20, 2017.

Pippa Middleton's wedding to James Matthews promises to be one of the biggest ceremonies this year, and a ton of preparations are being undertaken for the huge event. Although Middleton's walk into the wedding aisle will not be as public as her sister's, a lot of curiosity and controversy has revolved around the upcoming nuptials all the same.

The event will cost somewhere around £125,000 — around $163,000 — according to the Daily Mirror. The dress alone will cost £10,000 or about $13,000, and it is expected to be one of the highlights of the big wedding.

Around 350 guests will be looking forward to joining the newlyweds in their celebration, which will take place in the back garden of the estate of Pippa Middleton's parents.

Another incidental highlight of Pippa Middleton's wedding to James Matthews will be the appearance of Prince Harry, together with his girlfriend. UK media are already tracking Meghan Markle as she touched down in the country earlier to prepare in advance for Middleton's wedding, as reported by the Daily Mail.

The "Suits" star and her boyfriend Prince Harry will join the celebration as a couple at the event in Berkshire — a public appearance that will put to rest once and for all any lingering doubts about their relationship being official.

Prince Harry and Meghan Markle will join another royal couple in the celebrations. Catherine, the Duchess of Cambridge, sister of the bride, and Prince William, Duke of Cambridge and Prince Harry's older brother, will be present at the lavish event as well.

The 35-year old American actress was immediately taken to Kensington palace straight from Heathrow Airport on Tuesday, May 16. Meanwhile, speculations are already swirling on what outfit Markle will put together for the huge wedding bash.