Kate Middleton wore her first maternity dress to a charity event at the National Portrait Gallery on April 23.

The Duchess, due in July appeared in a powder blue 50’s-style Emilia Wickstead cocktail dress with a modest neckline and a low cut in the back. She sported a high pair of grey suede Ruper Sanderson heels, and had her hair curled and swept partly back from her face.

Middleton came to celebrate the work of The Art Room, which helps school children increase their self-esteem, self-confidence, and independence through drawing, painting, and modeling. This was one of the first charities the mother-to-be took up as a royal figure, the Daily Mail reported.

That evening was the launch of the Pledge for the Future appeal, and a celebration of their 11th anniversary.

The Duchess met with some of the children who had benefited from the charity's help, and the staff who work with them. She made a speech, praised the way the organization helped children stay within the education system "and fulfill their potential," according to the report.

Middleton, an art history major at St. Andrews University used her passion to voice her support for the charity.

"I am a firm believer in the power of art to make a difference and The Art Room makes this on a daily basis," she said.

The charity's founder and director Julie Beattie said, "The Duchess's continued commitment and endorsement of our work has been an invaluable asset in securing the foundation and laying the path for future growth."

The charity also announced the two new projects to be launched in Ealing, west London, and Edinburgh.

See photos of the Duchess here.