IT is one of the hardest jobs in sport.

With the eyes of two billion people across the world watching and hundreds of thousands of pounds of prize money at stake, it is not a role for the faint-hearted.

However, it is a challenge that cool, calm and collected Southampton student Kirsty Donaldson is taking in her stride.

The 21-year-old will officiate as a line judge at the Wimbledon tennis championships, which start on Monday.

At the heart of the action she will take make-or-break decisions which could affect the result of the world-famous tournament.

She took to Centre Court a few days early to model brand new uniforms designed by top fashion house Ralph Lauren.

The £6m designer makeover for Wimbledon court officials sees 1930s-style outfits in blue and cream replacing the old green kit.

Kirsty will be keeping her wits about her when she takes on the high-pressure job.

As well as being a keen tennis fan, Kirsty is a promising golfer who is currently studying in the US on a sports scholarship.

The former Thornden School and Tauntons College student, from Highfield, told the Daily Echo: "It is an amazing experience and being involved at Wimbledon is incredible.

"At first it was a bit daunting but now I'm used to it and it's fine. What I see, I call. I am full of excitement and can't wait to get started.

"Seeing the top players and being part of such a huge tournament is fantastic."

With balls thundering across the court at speeds of more than 100mph, Kirsty has to keeps her feathers well and truly unruffled.

The job of deciding whether a ball is in or out, has been famously dogged in controversy over the years and some judges have felt the full frustrations of the likes of John McEnroe and Ilie Nastase, but Kirsty says she has never been on the receiving end of a volley of abuse.

Last year she officiated at the men's Wimbledon final between Roger Federer and Andy Roddick.

Kirsty became involved in line judging six years ago after taking part in a youth training programme for junior tennis players.

She will be joined at Wimbledon by fellow line judge, 24-year-old Matt Saxby, also from Highfield.

The former pupil at St George Catholic School in Swaythling has travelled across the world taking part in major tournaments. His highlights have included the 2004 men's Wimbledon final and the Australian Open Women's final this year.

"I am very keen on tennis myself so the next best step to making it as a player is to be there as an official," said Matt, of Brookvale Road.

"You learn to deal with the pressure but you get used to it after a while and it becomes enjoyable."