Pippa Middleton ties the knot with James Matthews as royal family watches on

Pippa Middleton, the sister of Catherine, Duchess of Cambridge, has married financier James Matthews in a small English country church with a party of royals in attendance.

Some of the youngest members of the royal family played important roles on the day — three-year-old Prince George and two-year-old Princess Charlotte arrived with their mother Catherine and acted as a page boy and a flower girl respectively.

Ms Middleton arrived in a open-top car accompanied by her father, waving to crowds gathered near St Mark's church in Englefield, about 80 kilometres west of London.

Prince William walked up to the church with his younger brother Prince Harry.

Tennis champion Roger Federer and his wife Mirka were also among guests at the ceremony.

After the ceremony, a private reception was held at the bride's parents' estate in nearby Bucklebury.

The airspace above both villages was closed to prevent press crews from flying overhead or launching drones to get video footage.