Kate Middleton recently returned to her royal duties, but you might not have heard about her latest outing. Catherine, Duchess of Cambridge, paid a visit to a women’s prison outside London Friday. Unlike the Duchess’ other royal outings, this one was not announced by Kensington Palace.

According to People, the palace asked that the media “keep quiet” about her visit to HM Prison Send in Woking, England, until after it occurred. During her visit Kate reportedly met with inmates who are dealing with drug and alcohol addiction issues and listened to their stories. "I am grateful to the women I met for sharing their difficult personal stories with me," the Duchess said

The Duchess’ visit was in support of the Rehabilitation for Addicted Prisoners Trust (RAPt). The charity aims to help those in prison and in the community dealing with addiction overcome their issues and "lead positive lives." The Duchess also met with the founders of the organization. RAPt has since shared photos of Kate during her visit:

Kate’s visit to the women’s prison is her second public outing since returning from maternity leave. The 33-year-old royal started her leave in May following the birth to her second child, Princess Charlotte of Cambridge. She returned to her duties on Sept. 17, visiting the charity Anna Freud Centre in London. The charity aims to help children and adolescents suffering from mental health issues.

The Duchess followed her return to her royal duties with an appearance at the Opening Ceremony and first match of the Rugby World Cup 2015 between England and Fiji at Twickenham Stadium in London on Sept. 18. Her husband, Britain’s Prince William, Duke of Cambridge, and brother-in-law Prince Harry accompanied her to the sporting event.