Duchesses Kate and Meghan proved it is all about the hats as they stepped out with their husbands and other members of the royal family to celebrate Commonwealth Day.

Kate, the Duchess of Cambridge, color-blocked in a red Catherine Walker coat paired with a red hat.

PHOTO: Britain's Prince William and Catherine, Duchess of Cambridge, arrive to attend a Commonwealth Day Service at Westminster Abbey in central London, March 11, 2019.
Ben Stansall/AFP/Getty Images
Britain's Prince William and Catherine, Duchess of Cambridge, arrive to attend a Commonwealth Day Service at Westminster Abbey in central London, March 11, 2019.

Meghan, the Duchess of Sussex, paired her white coat, reportedly by designer Victoria Beckham, with a white hat.

PHOTO: Meghan, Duchess of Sussex and Prince Harry, Duke of Sussex attend the Commonwealth Service on Commonwealth Day at Westminster Abbey on March 11, 2019 in London.
Chris Jackson/Getty Images
Meghan, Duchess of Sussex and Prince Harry, Duke of Sussex attend the Commonwealth Service on Commonwealth Day at Westminster Abbey on March 11, 2019 in London.

The sisters-in-law joined their spouses, Prince William and Prince Harry, at Westminster Abbey for a Commonwealth Day Service with Queen Elizabeth II, Prince Charles and Camilla, the Duchess of Cornwall, and Prince Andrew.

PHOTO: Members of Britain's Royal family leave after attending the Commonwealth Service at Westminster Abbey in London, March 11, 2019.
Pool via AP
Members of Britain's Royal family leave after attending the Commonwealth Service at Westminster Abbey in London, March 11, 2019.
PHOTO: Queen Elizabeth II leaves following a Commonwealth Day Service at Westminster Abbey on March 11, 2019, in London.
Jack Taylor/Getty Images
Queen Elizabeth II leaves following a Commonwealth Day Service at Westminster Abbey on March 11, 2019, in London.

Meghan was seen talking with Kate and sharing a laugh with Prince Charles at the service, which celebrates the 53 Commonwealth countries around the world.

Prior to the service, Prince Harry and Meghan, wearing an embellished green coat dress reportedly by Erdem, made a visit to Canada House in London.

PHOTO: Britain's Prince Harry and Meghan, Duchess of Sussex attend the Commonwealth Day Youth Event at Canada House in London, March 11, 2019.
Chris Jackson/Pool Photo via AP
Britain's Prince Harry and Meghan, Duchess of Sussex attend the Commonwealth Day Youth Event at Canada House in London, March 11, 2019.

The couple, who are expecting their first child next month, joined kids making maple taffy, a Canadian tradition, and met with young Canadians working in fashion, the arts, business and education, according to Kensington Palace.

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The expectant parents also received baby gifts of boots and a onesie featuring a maple leaf.

PHOTO: Britain's Prince Harry and Meghan, Duchess of Sussex receive baby gifts from Canadian High Commissioner to the United Kingdom Janice Charette as they attend a Commonwealth Day youth event at Canada House in London, March 11, 2019.
Chris Jackson/Pool via Reuters
Britain's Prince Harry and Meghan, Duchess of Sussex receive baby gifts from Canadian High Commissioner to the United Kingdom Janice Charette as they attend a Commonwealth Day youth event at Canada House in London, March 11, 2019.

Meghan, who lived in Canada for several years while filming "Suits," was named on Friday, International Women's Day, as vice president of the Queen's Commonwealth Trust, an organization that supports and connects young leaders. Harry was named Commonwealth Youth Ambassador last year by Queen Elizabeth.