The Duke and Duchess of Sussex attended one of her last royal engagements in London on Thursday night.
Prince Harry and Duchess Meghan flew back to Britain to attend the annual Endeavour Fund Awards at Mansion House.
This was their first joint official engagement since announcing plans to step back from royal duties.
The couple - who married in 2018 and are parents to nine-month-old son Archie - are due to formally end their official duties on March 31.
Despite this, the Queen has reportedly told the Duke and Duchess of Sussex that they will "always be welcomed back" into the royal life.
The Duke recently held a four-hour meeting with his grandmother, and she is said to have told him the door is always open if he and his spouse change their minds.
The monarch reportedly told him: "You are much loved and will always be welcomed back."
A royal source said at the time: "The Queen had a lot to talk to Harry about and this was the ideal time for them to both say their piece.
"When Harry and Meghan announced they wanted to quit it all happened very quickly and it was very stressful for all concerned.
"Sunday was the first time the Queen has had the chance to talk to Harry on his own and really find out what his plans are. It was a much more relaxed environment and they were both able to speak their mind."
The Queen is believed to be "very upset" by the Duke and Duchess' decision to leave, but the talks are said to have "cleared the air" between them.
The insider added: "She made it very clear to him that he and Meghan are always able to come back if they change their minds and she will welcome them with open arms.
"Hopefully the chat cleared the air and the way forward is looking more positive."