Keira Knightley

Keira Knightley

Keira Knightley's ex-boyfriend Rupert Friend is engaged.

The British actor, who split from the 29-year-old star in 2011 after five years of dating, is set to marry Paralympian and model Aimee Mullins, 38, after proposing after more than a year of dating.

The couple's happy news was announced at L'Oréal Paris' Women of Worth Celebration in New York City on Tuesday night (02.12.14), when the blonde beauty, who is an ambassador for the cosmetics company, took to the stage to introduce one of this year's honorees.

A source told PEOPLE.com: "[L'Oréal] gave her a congratulatory shout-out when calling her up to the stage, which prompted a ton of applause from the audience.

"It was really sweet because Aimee was tight-lipped about it earlier in the night, not wanting to take attention from the honourees."

Aimee - who was born with a medical condition that resulted in the amputation of her lower legs - then celebrated the news with 'Homeland' star Rupert, 33.

An eyewitness said: "He was very doting the whole night, pulling out her chair, opening the car door. They were really adorable, just enjoying the night and each other's company."

Rumours the duo are set to tie the knot first start swirling in October and a source told the MailOnline at the time: "They are engaged. They come on set together holding hands and are obviously very much in love."

Rupert and Keira split following speculation that gruelling work commitments had driven them apart.

The 'Imitation Game' beauty married the Klaxons rocker James Righton, 31, in France in May 2013.