Prince William and Kate Middleton
Kate Middleton and Prince William are thrilled with Prince Harry and Meghan Markle's engagement. Pictured: Prince William and Middleton pose for the official tour portrait for their trip to Canada and California in the Garden's of Clarence House on June 3, 2011 in London. Getty Images/Chris Jackson

Kate Middleton has extended her well-wishes to Prince Harry and Meghan Markle for their engagement and upcoming wedding.

The Duchess of Cambridge was all smiles on Tuesday when she stopped by the Foundling Museum in London. It was the first time Middleton was spotted after the "Suits" star and Prince Harry's engagement was announced on Monday. When asked about it, Prince William's wife said she and her husband are ecstatic about Markle and Prince Harry tying the knot.

"William and I are absolutely thrilled," Middleton told reporters (via People). "It's such exciting news. It's a really happy time for any couple and we wish them all the best and hope they enjoy this happy moment."

Shortly after announcing Markle and Prince Harry's engagement, Kensington Palace released a statement from Prince William and Middleton expressing their thoughts regarding Prince Harry and Markle's decision to tie the knot. "The Duke and Duchess of Cambridge said of the engagement: 'We are very excited for Harry and Meghan. It has been wonderful getting to know Meghan and to see how happy she and Harry are together,'" the palace posted on Twitter.

Aside from Middleton and Prince William, Queen Elizabeth II and Prince Philip also released a statement regarding the big news, saying they "are delighted" for the newly engaged couple and that they "wish them every happiness."

Meanwhile, Prince Harry's father, Prince Charles, and Camilla Parker-Bowles wished him and Markle happiness as well. "We're thrilled. We're both thrilled. We hope they'll be very happy indeed," they wrote.

As for Middleton's visit to the museum, the soon-to-be mom-of-three donned a black dress by Kate Spade. The Duchess of Cambridge met the families and children who have benefited from the museum's education and outreach programs. The Foundling Hospital was established in 1739 by the Thomas Coram, a philanthropist. It was intended to care for babies who are at risk of abandonment. It's the first children's charity and public art gallery in the U.K.

While Prince Harry is prepping for his wedding with Markle, Middleton and Prince William are busy with their royal duties. On Friday, the couple attended the Royal Variety Performance where she seemed to channel Elsa from "Frozen" with her ice blue gown.

Last Wednesday, Prince William and Middleton went off-roading when they visited the Land Rover factory in Birmingham, England. Later that day, they also visited the Ashton Villa Football Club and chatted with the children on the soccer field.