Prince Harry's bride-to-be has made her first public appearance with Queen Elizabeth II.

Britain's Prince Harry and Meghan Markle, arrive for the Commonwealth Service at Westminster Abbey in London, Monday March 12, 2018. (Yui Mok/PA via AP)

Britain's Prince Harry and Meghan Markle, arrive for the Commonwealth Service at Westminster Abbey in London, Monday March 12, 2018. (Yui Mok/PA via AP)

Meghan Markle joined the queen and other senior royals Monday at the Commonwealth Day service at London's Westminster Abbey.

It marked another milestone in Markle's path to joining the British monarch's family. The American actress is set to marry Harry on the grounds of Windsor Castle on May 19.

Britain's Prince Harry's fiancee Meghan Markle leaves the Commonwealth Service at Westminster Abbey, London Monday March 12, 2018. (Yui Mok/PA via AP)

Britain's Prince Harry's fiancee Meghan Markle leaves the Commonwealth Service at Westminster Abbey, London Monday March 12, 2018. (Yui Mok/PA via AP)

Harry and Markle were greeted with screams and shouts from some members of the public when they arrived at the venerable abbey.

They were joined by Prince William and his wife, Kate, Prince Charles, and other royals.

Meghan Markle receives flowers as she leaves after attending the Commonwealth Service at Westminster Abbey in London, Monday, March 12, 2018.  (AP Photo/Kirsty Wigglesworth, pool)

Meghan Markle receives flowers as she leaves after attending the Commonwealth Service at Westminster Abbey in London, Monday, March 12, 2018.  (AP Photo/Kirsty Wigglesworth, pool)

Meghan Markle talking to children as she leaves the Commonwealth Service at Westminster Abbey in London, Monday March 12, 2018. (Yui Mok/PA via AP)

Meghan Markle talking to children as she leaves the Commonwealth Service at Westminster Abbey in London, Monday March 12, 2018. (Yui Mok/PA via AP)