It was a date night for Prince William and Kate Middleton at the Noël Coward Theatre in London on Tuesday.

Prince William and Kate Middleton visited the Convent Garden theatre to watch "Dear Evan Hansen," a Tony award-winning musical play that focuses on mental health.

Kate arrived at the event in a 525-pound black custom ankle-length tweed dress by Eponine that featured embellished buttons in the front. The 38-year-old paired the dress with 525-pound Romy ombré glitter pumps by Jimmy Choo, which she had earlier worn at the BAFTA awards and the Addiction Awareness Week charity gala last year. The most expensive piece in Kate's look was a new glittery clutch worth 675 pounds, that matched the grey and silver colours of her Jimmy Choo, reports Mail Online.

The mother-of-three kept her makeup light with a hint of blush and winged eyeliners, styled her hair in a wavy blowout, and wore a pair of diamond earrings. The chandeliers earrings that Kate previously wore in 2017, are a loan from Queen Elizabeth II, though the British monarch has never worn them herself. Prince William, meanwhile, looked dapper in a crisp white shirt underneath a navy blue suit and spotted tie. A series of pictures from the special evening was posted on the couple's Kensington Royal Instagram account.

The special performance was held in aid of The Royal Foundation, the charity organisation of the Duke and Duchess of Cambridge. Mental health awareness is a cause close to the foundation as well as Kate. "@GiveUsAShoutInsta," a free and confidential 24/7 UK text messaging helpline launched by the foundation that supports people in mental health crisis, was also one of four not-for-profit partners of the play.

The musical shows the struggles of an anxiety-ridden boy, Evan, who is trying to connect in a hyper-connected world. The act which has been running at the Noël Coward Theatre since November last year had won six Tony awards after its Broadway debut in 2016.

At the theatre in central London, the royal couple met the members of the cast and also engaged in a conversation about mental health with the play's author Steve Levenson, and composers Justin Paul and Benj Pasek. They reportedly praised the British cast for holding an American accent for the entire play.

kate middleton
Catherine, Duchess of Cambridge receives flowers as Prince William, Duke of Cambridge smiles after a tour of the Jaguar Land Rover's Solihull manufacturing plant on November 22, 2017 in Birmingham, England Getty

In a keynote address after the play, William said: "One of the issues that we care passionately about is mental health and we are pleased that Dear Evan Hansen is helping to start important conversations between parents and teenagers about this important subject."