Duchess Kate looks gorgeous for first-ever solo outing with the queen

On Tuesday morning, Duchess Kate and Queen Elizabeth stepped out for their first-ever joint appearance.

The royal duo looked like old friends as they arrived by car together at King's College in London to officially open Bush House. This event marked Kate's first outing with the queen without any other royal family members in attendance.

Kate stunned in a stylish grey coat dress by Catherine Walker, one of her go-to designers, for the very rare occasion. She completed her look with a Sylvia Fletcher fascinator, black heels and little black Mulberry bag. According to the Daily Mail, Kate wore a hat "likely to be a sign of respect to the monarch."

The queen wore a lovely pink cashmere coat with black detailing by Stewart Parvin, along with a matching pink hat. The 92-year-old royal finished off her springtime look with simple black accessories and a classic pearl necklace.

Kensington Palace also shared on Twitter that after Duchess Kate's morning outing with the queen she will visit the Foundling Museum "to understand how they use art to make a positive contribution to society by engaging with vulnerable and marginalised young people."

See Kate's latest outing with husband Prince William below: