Pippa's friend Mike, who's parents are the Earl and Countess of Romney, is a director at multinational investment company Black Rock. He tied the knot with Lucy Beaumont, daughter of Viscount and Viscountess Allendale, in the market town Hexham, the Beaumont's family seat.
Pippa, 29, journeyed Northumberland for the ceremony unaccompanied by her boyfriend Nico Jackson. The party planner and Waitrose columnist's azure outfit was matched with grey suede heels, a similarly hued clutch bag and headpiece. Wearing her brunette locks in an elegant up'do, Pippa drew attention to her dramatic magenta, black and grey beaded necklace.
The aunty-to-be was marking almost two years since she turned heads as a bridesmaid at sister Kate Middleton's wedding to Prince William, which was also attended by the now newlywed couple, Mike and Lucy.
On Wednesday Pippa was spotted wearing an equally elegant outfit when she went to the Mary Hare School for deaf children in her Berkshire hometown. Pippa attended the opening of the centre's £2million boarding house, having recently become an ambassador for the school.
Pippa appeared to have taken some style tips from her sister Kate, choosing to wear a Tory Burch "Emma" bouclé dress and matching jacket, accessorised with blue heels, similar to the outfit The Duchess of Cambridge sported at the National Review of Queen's Scouts.