- Catherine will become patron of two arts-related charities, reflecting her personal interests
- The charity Action on Addiction hopes her support will help change people's attitudes
- Catherine is in talks with the National Portrait Gallery about her first official portrait
- Diana, Princess of Wales, was known for her work to help those with HIV and AIDS
Catherine, the Duchess of Cambridge, has taken the first step toward carving out her own public role with the announcement Thursday of the U.K. charities she has chosen to support as patron.
They include a group that provides art therapy to children, the National Portrait Gallery and an organization that helps those struggling with addiction.
Until now, the Duchess of Cambridge's official public appearances have been in a supporting role to her husband, Prince William.
But after three months of research, Catherine has chosen the causes she wants to support in her own right, two of which reflect her personal interests as a student of art history.
One is the Art Room, a tiny charity that helps disadvantaged children express themselves, develop self-esteem and learn life skills through art.
Juli Beattie, the Art Room's founder and director, said it was "completely overwhelming" to have such a high-profile figure lend her name to the charity. "The duchess is fascinated by art," she told CNN.
Sandy Nairne, director of the National Portrait Gallery, said Catherine's knowledge of the subject had also made an impression with staff there.
"When she spent time with us, it was very clear she was showing a strong interest in our collection, in the way we work with the young people, how we develop our research, how we make our exhibitions," Nairne said.
"All of those things she wanted to know more about. Clearly she'd done her studies well at St. Andrews (University), and that was absolutely showing," he said.
The National Portrait Gallery has a famous collection of royal paintings and photographs -- and the duchess is already in talks to have her first official portrait commissioned, Nairne said.
Catherine will also become patron of East Anglia's Children's Hospices, which help children and young people with life-threatening conditions.
Perhaps more controversially for some, she will become patron of Action on Addiction, which runs a network of addiction treatment centers across England.
The hope is that her patronage can help remove the stigma from addiction in the way that William's mother, Diana, Princess of Wales, changed public attitudes through her support for people diagnosed with HIV and AIDS worldwide.
Nick Barton, chief executive of Action on Addiction, said: "It's not an easy subject for some people -- but I think this sort of patronage will change that."
The charity helps those with addiction issues, as well as providing support for families of addicts, training for professionals and backing for research.
The duchess has also announced that she will be hitting the outdoors as a voluntary helper with the Scout Association, of which Queen Elizabeth II is the patron.
Chief Scout Bear Grylls, famous in Britain for his televised adventures in the wild, said: "I think what's lovely is that she's going to feel exactly the way young Scouts feel when they first join: a little bit nervous. But that's what scouting's about. You're part of a big family."
More than 400,000 young men and women are involved with the Scout Association across the United Kingdom.
Catherine is expected to volunteer primarily with younger members of the organization, helping out at Cub Scout and Beaver Scout groups near the north Wales home she shares with Prince William and elsewhere, her office said.
The late Diana, Princess of Wales, was defined by her charity work, whether supporting those with AIDS or campaigning for a ban on anti-personnel landmines.
The Duchess of Cambridge can expect plenty of attention in turn as she embraces her new roles.