Royals Kate Middleton and Prince William Step Out for First Joint Engagement Since Prince Louis' Birth The summit is part of the royal couple's ongoing work to reduce stigma surrounding mental health issues By Simon Perry Published on October 9, 2018 07:15 AM Share Tweet Pin Email Prince William and Kate Middleton are back on royal duty together — and taking their mental health campaign to the world stage. The royal couple, whose Heads Together initiative alongside Prince Harry has helped mainstream mental health discussions, attended the first meeting of its kind to unite politics, academics and health policy-makers on Tuesday. The inaugural Global Ministerial Mental Health Summit, co-hosted by the British government and the Organization for Economic Cooperation and Development (OECD), aims to help countries work together to address mental health issues. Last month, in a major speech, William, 36, spoke about workplace mental health, and last week, Kate, 36, highlighted the virtues of outdoor play in helping children’s well-being. (Tuesday’s outing marks the couple’s first joint venture since Kate wrapped up maternity leave following the birth of the couple’s third child, Prince Louis, in April.) James Gourley/REX/Shutterstock Inside the gathering at County Hall on the south banks of the River Thames in London on Tuesday, the royal couple heard presentations on two case studies of active mental health programs from the U.S. and Slovenia. Press Association via AP Images EDDIE MULHOLLAND/AFP/Getty Images Can’t get enough of PEOPLE’s Royals coverage? Sign up for our newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! The mother of three recycled a long-sleeved lilac Emilia Wickstead dress — she previously wore the piece last year while visiting Germany with her family — and sported her signature hairstyle, a bouncy blowout. She accessorized with a matching earring and necklace set, the Aspinal of London Mayfair bag and matching heels. Beretta/Sims/REX/Shutterstock Beretta/Sims/REX/Shutterstock James Gourley/REX/Shutterstock Every Gorgeous Photo of Kate Middleton’s Return to Royal Duty from Maternity Leave William and Kate saw how a Colombian artist, Dairo Vargas, captured the summit in a unique piece of art — even taking turns to dab some paint on the piece themselves! After Kate carefully swiped the paintbrush — after William volunteered her as “the arty one” — she handed it over to her husband, who was clearly unsure in his artistic abilities. “This is how you probably ruin a picture,” he warned. The royal couple also visited a “friendship bench,” which is part of an initiative to teach elderly women in Zimbabwe the skills to become city lay health workers. Eddie Mulholland - WPA Pool/Getty Images Eddie Mulholland - WPA Pool/Getty Images They also visited the exhibition area and met with representatives to hear about various organizations’ mental health campaigns and programs.