In her new role Meghan will help highlight the Trust's work with young people across the Commonwealth, particularly supporting women and girls.

The announcement was made a few hours before the duchess takes part in a discussion panel, organised by the Trust, of leading feminists and national figures to mark International Women's Day.

Nicola Brentnall, the Trust's chief executive, said: "We are particularly delighted that the first opportunity of formally working together with Her Royal Highness comes on International Women's Day.

"This squares perfectly with our focus on amplifying the work and contribution of those furthest away from power.

"Women across the Commonwealth and the globe often face the biggest impediments to success.

"So we are delighted to have our vice-president's support in helping others to overcome those obstacles."

Last year the Duke of Sussex said Meghan was "hugely excited" to be joining him in his work as Commonwealth youth ambassador, a post bestowed by the institution's head, the Queen.

The trust works to champion, fund and connect young leaders around the world who are driving positive social change, serving their communities and providing hope, work and self employment opportunities for others.

Lord Geidt, the Trust's chairman and the Queen's former private secretary, said: "The support and encouragement which Her Royal Highness will bring to the young leaders with whom we work promises to have a profound effect."

During the discussion Meghan will appear alongside singer Annie Lennox, former prime minister of Australia Julia Gillard and others to debate a range of issues affecting women today.

Australian Associated Press