Duchess Kate steps out in lavender for joint appearance with Prince William after maternity leave

Lovely in lavender!

On Tuesday morning, Duchess Kate stepped out alongside Prince William for her first joint public appearance since giving birth to the couple's third child, Prince Louis. The duo attended the Global Ministerial Mental Health Summit -- the first meeting of its kind -- in London.

The mother-of-three looked beautiful in a long-sleeved, light purple Emilia Wickstead dress. Kate had previously worn the same dress during the royal family's European tour just last year (see all of her looks here).

She completed her elegant look with a matching earring and necklace set, nude heels, a taupe Mayfair Bag from Aspinal of London and, of course, her signature blow out. William complemented his wife in a black suit and a thin, patterned maroon tie.

The Duke and Duchess of Cambridge are no strangers to mental health initiatives as they, with Prince Harry, created Heads Together which "combines a campaign to tackle stigma and change the conversation on mental health with fundraising for a series of innovative new mental health services."

Earlier this month, Kate made her return from her six-month-long maternity leave when she visited Sayers Croft Forest School and Wildlife Garden, where she interacted with school children and played with them outdoors.

The duchess is in the midst of a very busy month as she is expected to attend Princess Eugenie's wedding later this month and her sister, Pippa Middleton, is due to have her first child this fall.

See more of Kate's first appearance postpartum below!