Meghan Markle didn't use her Duchess title in her newborn daughter's birth certificate; amid increasing calls to strip her and Prince Harry of their royal titles for their repeated attacks against Buckingham Palace.

However, her husband still used his royal title, and was mentioned as the Duke of Sussex on Lilibet Diana Mountbatten-Windsor's birth document, which has been obtained by People magazine.

The newly-released birth certificate of Lili shows that she was born on June 4 at 11:40 a.m. in the Santa Barbara Cottage Hospital in California. Her mother has been listed by her full name Rachel Meghan Markle, as the document required her legal name and her maiden name, but she did not use her Duchess of Sussex title which was gifted to her by Queen Elizabeth II upon her marriage to Prince Harry. The move comes just months after she used her title as the author's name on her children's book "The Bench."

Meanwhile, Harry has listed himself as "The Duke of Sussex" for his first name and "His Royal Highness" as his last name. The couple had promised the monarchy not to use their HRH titles after exiting as working royals in March last year, but officially they still hold the honours.

Lili's birth certificate is in contrast with that of her elder brother Archie Harrison. The document of the two-year-old was made public 11 days after his birth in May 2019, in which his father was listed as "His Royal Highness Henry Charles Albert David Duke of Sussex," while her mother was "Rachel Meghan Her Royal Highness The Duchess of Sussex."

The couple's occupations on their eldest child's certificate were listed as "Prince" and "Princess of the United Kingdom." Although Meghan only holds a Duchess title, she is technically a Princess as she is married to a Prince of the United Kingdom. In the case of Lili's document, they did not need to mention their occupation, as the Californian birth document does not require one.

Lili is the 11th great-grandchild of the Queen and has also been named after the monarch. The 95-year-old coined "Lilibet" as a nickname for herself as she had difficulty pronouncing Elizabeth in her childhood.

Prince Harry and Meghan Markle
Prince Harry and Meghan Markle. Photo: AFP / Ben STANSALL