Pippa & Kate Middleton
Kate Middleton will not be Pippa Middleton’s bridesmaid on her big day. Pictured: Middleton sisters Gentlemen’s Singles final match between Roger Federer of Switzerland and Andy Murray of Great Britain in London on July 8, 2012. Getty Images/Clive Brunskill

Pippa Middleton was Kate Middleton’s bridesmaid on her royal wedding with Prince William. However, the Duchess of Cambridge will not have the same role on her sister’s big day.

Pippa and fiancé James Matthew are about to exchange their “I Dos” next week. Initially, many expected her to return the favor and have Kate as her bridesmaid. After all, that is what most sisters do. However, it is confirmed that William’s wife will not have the same role and the reason is due to etiquette, Mirror reported.

Bridesmaids are traditionally chosen from a group of single women in marriageable age within the bride’s family. The main bridesmaid is also called the chief bridesmaid or maid of honor. If one is married then she is dubbed as the “matron of honor.” Thus, Kate does not qualify to be Pippa’s bridesmaid.

READ: Meghan Markle is already preparing for her gown for Pippa Middleton‘s wedding

The Duchess of Cambridge is still expected to be part of Pippa’s wedding. However, it is still unknown what her part will be.

“Kate would upstage her sister. It’s a tricky situation for Pippa. She would want her sister by her side, as who else would she trust to make things go well?” royals author Judy Wade told People. “But if your sister is a future Queen, she is going to upstage the bride and draw attention. Kate would want to be in the background as much as possible.”

Kate has been supportive of Pippa on her wedding. In fact, the Duchess of Cambridge was spotted in her younger sister’s home in London. William’s wife kept a low profile and dressed casually in a cable knit jumper and black skinny jeans. She also traded her signature high heels with a pair of Superga sneakers, Daily Mail reported.

Kate also joined Pippa on her bachelorette party in Meribel, France, while William made headlines for dad dancing in a different ski party in Switzerland. Kate has been there for her sister in every stage of her wedding preparations.

“Pippa loves skiing so it was her first choice for a hen weekend,” a source who attended the party told The Sun. “They stayed in a really exclusive catered chalet with maids and chef, who ensured that they were totally spoilt. The owners also wanted to impress their royal guests so the girls were showered with gifts.”

Pippa and her guests on her hen party received Swatch watches, UGG slippers, leather-bound notebooks and bespoke fragrances.

Meanwhile, Kate and William’s children Prince George, 3, and Princess Charlotte, 1, will be part of the entourage as page boy and flower girl. For a family who dresses their children in shorts, the same clothing is expected in Pippa’s wedding. This is a tradition that they are expected to keep.

As for Pippa’s wedding guests, “Suits” star Meghan Markle is expected to attend the nuptials, reception and evening after-party with Prince Harry. The actress is an exception to the bride’s “no ring, no bring” policy because she is not yet engaged or married to Kate’s brother-in-law but will be attending the event.

Who do you think will be Pippa’s maid of honor? What will be Kate’s role in her sister’s wedding? Drop a comment below.