Prince William and Kate Middleton were all smiles at their first royal engagement since Prince Louis was born

Kate Middleton and Prince William were seen out at a royal engagement on Oct. 9, their first official joint appearance since the birth of Prince Louis in April. As announced in May, Middleton took a maternity leave after Louis’s birth, and this engagement marks her second official outing since returning from leave (and the first that the royal couple attended together).

The Duke and Duchess of Cambridge attended the inaugural Global Ministerial Mental Health Summit, which was co-hosted by the British government and the Organization for Economic Cooperation and Development (OECD).

The summit was held at County Hall on the south banks of the River Thames in London. The royal couple listened to two presentations on effective mental health programs in the United States and Slovenia.

Mental health is an important cause to the royal couple, and it’s the focus of their Heads Together initiative, which raises money for new mental health services and aims to end the stigma around mental illness. Prince Harry also spearheads the project with them.

“The challenge that so many people have is not knowing how to take that first step of reaching out to another person for help,” Middleton said in a speech last year. “Admitting that they are not coping. Fear, or reticence, or a sense of not wanting to burden another, means that people suffer in silence — allowing the problem to grow larger and larger unchecked.”

While at the summit, the couple met Dario Vargas, an artist who is working on a painting at County Hall. They were asked to add their own additions to the painting, though Prince William declined. “This is how you properly ruin a picture,” he quipped.

Middleton added a white stroke to the piece and Prince William praised her creative skills, declaring, “She’s the arty one!”

The couple was also asked to pose naturally while sitting on a “friendship bench,” which caused them both to erupt into giggles. Check out the sweet moment in the photo below.

We can’t wait to see more of the royal couple out and about!