However, it’s understood that Kate, 34, is well aware that her regal status, being married to the heir to the British throne, could be distracting on what should be the most special day of her 32-year-old sister’s life.
‘If your sister is a future Queen, she is going to upstage the bride and draw attention,’ veteran royals author Judy Wade states. ‘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? [But] Kate would upstage her sister. Kate would want to be in the background as much as possible.’
However, Kate isn’t the only one with the potential to upstage their sibling on their big day.
Fans of upmarket UK reality series Made In Chelsea will be well aware that former star Spencer Matthews is in fact the younger brother of Pippa’s new fiancé, hedge fund manager James Matthews, 40.
The 27-year-old is known as quite the lothario, having bedded almost all of his co-stars – and subsequently cheated on them – during his four years on the popular show.
In 2012, he even stared in the UK version of The Bachelor – despite still being in a relationship with MIC’s Louise Thompson at the time.
More recently, Spencer was kicked out of the Australian ‘jungle’ last year while competing on the UK version of I’m A Celebrity… Get Me Out Of Here! after admitting to steroid abuse.
He’s now in talks to re-enter to competition – though if he does, he’ll be face-to-face with recent ex Lauren Hutton, whom he broke up with last August amid cheating allegations.