The Duchess of Cambridge expressed her heartache after watching the BAFTA-winning documentary, "For Sama," since it reminds her of her son, Prince Louis.

Kate Middleton and her husband, the Duke of Cambridge, were among the celebrity guests on Sunday's 73rd British Academy Film Awards (BAFTA). They saw some of the award-winning shows, documentaries and movies, and talked to the guests, including filmmaker Waad al Kateab, who shared details about her conversation with the Duchess.

According to the 29-year-old Syrian journalist and activist, the royal approached her and commended her work on the Allepo documentary. She said the Duchess felt heartbroken after she saw the documentary, because it made her think about her youngest child, Prince Louis.

"I was heartbroken. My boy is a similar age to Sama. You are a great inspiration for every woman," Kateab quoted Kate Middleton, according to Hello Magazine.

The Duchess of Cambridge thought Kateab's work is "amazing" and that it is "so engaging." The filmmaker admitted that she was "speechless" at Kate Middleton's praise.

"For Sama" chronicles Kateab's life in war-torn Syria after the uprising in 2011. It tells of her struggles all through five years of the war, as she experiences the uprising first hand while going through the motions of life, including falling in love, getting married, and having a child. The documentary tells of the family's hardships as they try to raise their daughter, Sama, amid the war. The story was taken from a woman's perspective, specifically, from Kateab, who filmed the events of the war herself.

"We shouldn't be here. In 2016, we were in a basement in a hospital when we heard the shelling of the bombs all around us. I thought I should bury my footage in case we didn't make it – it needed to be saved," Kateab said in her acceptance speech, adding, "There are still bombings of 3.5million civilians. They should hear Britain will not let that happen again."

"For Sama" won Best Documentary Award at the BAFTAs. Kateab attended the event with her husband and Sama, who is now four years old. The family now lives in London.

Prince William, Kate Middleton Pakistan tour
Prince William and his wife Kate explored Lahore's famous Badshahi Mosque -- one of the world's largest. Photo: AFP / AAMIR QURESHI