London, Oct 14 : Prince William’s girlfriend, Kate Middleton’s induction into the royal family appears to have intensified after she tried her hand at shooting with Prince Charles on a trip to Balmoral.

Middleton was pictured stalking deer on the 50,000-acre estate in Aberdeenshire, next to Charles, a move that is the clearest sign yet that she will one day become his daughter-in-law.

It is the first time Middleton had been photographed publicly with Prince Charles, making royal watchers speculate that she may soon become engaged to Prince William.

"This is a hugely significant step for Wills and Kate's relationship. This visit indicates how Kate is fully integrated into the royal way of life. But more importantly it shows Prince Charles and Camilla fully accept her,” News of the World quoted a royal source, as saying.

Dressed in a camouflage jacket, dark jeans, leg warmers and gaiters over her boots, Middleton could be seen at one point lying on the ground - seemingly to prepare the sights of her gun before shooting.

"Kate looked through the telescopic lens and fired. She looked pleased and smiled. Charles left after watching her get to grips with the rifle. He seemed pleased with how quickly Kate handled such a powerful weapon,” an onlooker said.

However, Kate’s outing has been slammed by animal rights groups, who say that the 25-year-old should not have been involved in the shoot.

"It beggars belief that the royal family believe it is fun to slaughter deer. I am very sad that Ms Middleton has been introduced to this cruel sport.

Presumably it is all part of her induction into a family with an appalling track record on blood sports,” a spokesperson for the League Against Cruel Sports told the Daily Mail.

A spokesman for Prince Charles said: “We do not act for Ms Middleton and so we have no comment to make. What the Royals do on the Balmoral estate is a private matter.”

William and Kate are spending a long weekend at Birkhall, Prince Charles’s home on the Scottish estate, which he took over five years ago when the Queen Mother died.

The couple are the guests of Prince Charles and the Duchess of Cornwall - thereby fuelling speculation of a possible engagement. (ANI)