Catherine, Duchess of Cambridge
Catherine, Duchess of Cambridge, and her husband Britain's Prince William (unseen) visit the Botanical Gardens in Christchurch April 14, 2014. Prince William and his wife are undertaking a 19-day official visit to New Zealand and Australia with their son, Prince George. Reuters/ Chris Jackson/Pool

Kate Middleton and Prince William are seen in public on a number of occasions but there is speculation in the media that Kate is very particular about what friends she will meet, particularly when they are William's friends. The Duchess, who was by her husband Prince William's side like a dutiful royal wife during their recent New York visit may not always choose to do the same as she does not like excessive partying and "drunken behaviour," says the media reports.

The Duchess has reportedly chosen to ignore William's friends on eight occasions including four marriages, two holidays and even a Christening ceremony of Zara Phillips's daughter Mia, reveals Daily Mail. The website also reports that the Duchess was mostly in her good health when she avoided many occasions and was seen shopping or going out to other places on the same day or a few days earlier.

The Duchess' absence was particularly noted when she did not attend the marriage ceremony of William's closest friend Tom van Straubenzee. William was Tom's best man. Kate was reportedly seen shopping on the same day, says the website.

The Duchess, who is currently five months pregnant, has been noticed for her anti-social skills quite often, says the website."People have noticed she's rarely by William's side when he socialises - it gives the impression she wants to avoid some of his friends," a source close to the royals tells the Daily Mail.

Another source added that people really wanted Kate to go out with William's friends as most of his friends are not very well acquainted with the Duchess. Another reason cited for Kate's absence from several occasions is that she likes a sober life and was reportedly put off by one particular incident when she met a few of William's friends who were really high on alcohol.

"She doesn't like drunken behaviour, but some of them like to party. One drunken incident recently put her off one of William's close female friends, and Kate wasn't afraid to let her know she disapproved of her sloppy behaviour," said a source close to the royals.