Fergie's girls: Beatrice and Eugenie

Princesses Beatrice and Eugenie and their mother at a charity event in March.

Fergie and Beatrice in Klosters in 1991.

Fergie with her daughters during a ski trip to Klosters in 1992.

Fergie, Beatrice and Eugenie on Eugenie's first day of school in 1994.

William, Harry, Beatrice and Eugenie skiing in Klosters in 1995.

Princess Beatrice with a school friend in 1998.

William, Harry and Beatrice attending Prince Edward's wedding in 1999.

Fergie and Beatrice cuddle up in Verbier, Switzerland, in 2001.

Fergie, Beatrice and Eugenie at a tennis match at Buckingham Palace in 2000.

Beatrice with William and Harry at a wedding in 2005.

Prince Harry and Eugenie share a joke at the Trooping of the Colour in 2006.

Prince William, Eugenie and Prince Andrew in London in 2006.

Beatrice and Fergie walk in the Fashion for Relief show in 2007.

Eugenie and Prince William at the annual Trooping of the Colour in 2007.

Beatrice and Eugenie in London in 2008.

Fergie, Beatrice and Eugenie attend a London film premiere in 2009.

Fergie and her girls attend a film premiere in Los Angeles in 2009.

Beatrice and her boyfriend Dave Clark after finishing the London marathon in 2010.

Beatrice's infamous royal wedding hat.

Eugenie with Kate Middleton at Derby Day in June this year.

Eugenie and Prince Harry cheer for their horses at Derby Day in June.

July 13, 2011: Thrust into the spotlight, it seems our pretty young royals are shrinking before our eyes. Reports are rife that Kate Middleton has become alarmingly thin since her big day, and Princess Beatrice, daughter of one of the world's most famous yo-yo dieters, has also drawn attention to her new slim figure.