Zara Phillips and Oliver Townend drop their competitive guards

Sharing a light-hearted moment, equestrians Zara Phillips and Oliver Townend may look like good friends in these pictures taken at the opening of the Burghley Horse Trials yesterday — but they will be fierce rivals when the event gets properly underway today.

Race rivals: Oliver Townend and Zara Phillips look like good friends

Ms Phillips, 28, the current eventing world champion and daughter of Princess Anne, will ride Glenbuck in the competition in Lincolnshire while Mr Townend, 26, will be on Three Wishes IV.

Sporty pair: Zara is engaged to rugyby player Mike Tindall

The Burghley trials are one of the top competitions in the three-day eventing world and climax with showjumping on Sunday. Mr Townend, who runs a stables in Shropshire, is considered to be one of the rising stars of British eventing and won the Badminton Horse Trials in May.

Ms Phillips, who lives in Gloucestershire, is in a relationship with Mike Tindall, the 30-year-old Gloucester and England rugby player.