The title of queen consort for Camilla is a request the queen made in February, on the eve of her Platinum Jubilee, marking 70 years on the throne.
"And when, in the fullness of time, my son Charles becomes King, I know you will give him and his wife Camilla the same support that you have given me, and it is my sincere wish that, when that time comes, Camilla will be known as Queen Consort as she continues her own loyal service," the queen said.
The statement marked the first time the queen had publicly addressed her daughter-in-law's role in the future monarchy.
When Charles and Camilla married in 2005, there was some debate as to what title Camilla, a divorcee, would take when Charles became king.
At the time of their wedding, a spokesperson for the couple suggested she would take the title Princess Consort.
Queen Consort is the title given to the spouse of a king, and under U.K. law, whoever is married to a king would immediately become that and be known as queen. There was some concern the public might resent Camilla being known as Queen Camilla, which is why this Princess Consort title was suggested.
With the queen's blessing, Camilla will now be known as Queen Camilla as her husband is now King Charles III.
At the time the queen's request was made public, Camilla, 75, called it a "great honor" to be given the title Queen Consort.
Camilla was at Balmoral with Charles and other royal family members on Thursday when the queen died "peacefully" in the afternoon, according to Buckingham Palace.
The rise of Camilla in the royal family and in the eyes of the public has been a transformation over the past nearly two decades.
"There was a concerted effort to rehabilitate Camilla's reputation, but she also did that herself by how she approached her situation and over time we have seen the public's perception of her really change," ABC News royal contributor Victoria Murphy said earlier this year. "And now we see her very much accepted and embraced as a future queen."
At one time, Camilla was blamed for the end of Charles' marriage to his first wife, the late Princess Diana, the mother of his two sons, Princes William and Harry.
She and Charles first met in the 1970s and remained friends during their respective marriages, each of which ended in the mid-1990s.
In an interview this year with British Vogue, Camilla said she had to "rise above" the press and public's scrutiny.
"It's not easy," she said. "I was scrutinized for such a long time that you just have to find a way to live with it. Nobody likes to be looked at all the time and, you know, criticized ... but I think in the end, I sort of rise above it."
During her nearly two decades as a member of the royal family, Camilla has dedicated herself to supporting Charles and championing her own causes, among them supporting victims of domestic abuse.
Camilla told British Vogue she plans to continue to advocate for causes closest to her heart as queen, saying, "You can't desert things that you're in the middle of. There's a lot of things to be done still."
She also described to the magazine the lives she and Charles lead behind-the-scenes, noting they can be like "ships passing in the night" due to their busy schedules.
"It's not easy sometimes, but we do always try to have a point in the day when we meet," she said. "Sometimes it's like ships passing in the night, but we always sit down together and have a cup of tea and discuss the day. We have a moment. It's lovely to catch up when we have a bit of time."
Describing the times they are away from the daily grind of royal life, Camilla added, "You know when we go away, the nicest thing is that we actually sit and read our books in different corners of the same room. It's very relaxing because you know you don't have to make conversation. You just sit and be together."