See Prince Harry and Meghan Markle's beautiful engagement photos

Britain's Prince Harry and his American fiancee Meghan Markle have released a series of portraits by New York-based fashion photographer Alexi Lubomirski to mark their engagement.

Lubomirski, a former assistant to Mario Testino, famed for his photos of Harry's mother Princess Diana, took the pictures this week at the royal retreat of Frogmore House, near Windsor Castle, west of London, where the couple are due to marry on May 19.

"A huge thank you to His Royal Highness Prince Harry and Ms Markle, for allowing me to take their official engagement portraits," he wrote in an Instagram post.

"Not only was it an incredible honour, but also an immense privilege to be invited to share and be a witness to this young couple’s love for each other. 

"I cannot help but smile when I look at the photos that we took of them, such was their happiness together."

Queen Elizabeth's 33-year-old grandson, Harry, fifth-in-line to the throne, and Markle, 36, who stars in the US TV legal drama Suits, announced their engagement last month.

Reuters