A dying boy was granted his last wish thanks to actress extraordinaire Helen Mirren.

Oliver Burton, a 10-year-old with Down sydrome who was diagnosed with terminal cancer, wanted more than anything to visit Buckingham Palace and have tea with Queen Elizabeth. However, the monarch's busy schedule did not allow for the visit with Oliver, despite the boy having only about 10 weeks left to live.

So, enter Dame Helen Mirren.

The 67-year-old actress is reprising her Oscar-winning role as the queen in the play “The Audience” and extended an invitation to Oliver for tea following her performance at the Gielgud Theatre in Westminster. Mirren dressed up in full Queen Elizabeth costume for the boy, who thanked her with a bouquet of flowers.

The two dined on tea and sandwiches, played with corgis from the show and Mirren even knighted Burton with her hand. The National/Regional Children’s Leukemia and Cancer Trust called the day “magical” for the boy, who has very little time left.

“Our incredibly brave Ollie has Tea with The Queen,” the trust wrote on Facebook. “You have made a very poorly boy achieve his biggest most wanted and dreamt about wish, thankyou all xx”

The boy’s mother, Catherine Burton, told the Leicester Mercury that Mirren completely fulfilled his last wish and even made him  believe he was with the real queen.

"Dame Helen was brilliant. She stayed in character the whole time and spent a lot of time talking to Oliver and drawing him out of himself,” she said. “She signed his British flag, which he waves all the time. Even now, if you ask him who he met recently, he smiles and waves the flag. He believes he met the real queen and that's fine by us. We were treated like royalty for a day. It has provided so many memories for friends and family. It gave us all such a lift."

And Mirren was just as happy to meet the boy. “It was a pleasure and a privilege to meet such a brave young man,” the actress told The Sun.

Oliver Burton, who hails from Leicester, was born with Down syndrome and was diagnosed with leukemia at 3 years old in 2006. The boy recovered from his first battle with cancer, but it returned again in 2010.

He eventually pulled through the second diagnosis, too, but was diagnosed again last Christmas. This time, though, the cancer is in his spine and bone marrow. Doctors say no effective treatment is possible at this point and told Burton’s family that he has only about 10 weeks left to live.

With such an unfortunate prognosis, the family made a support page for Oliver on Facebook in order to raise money to pay for things on his bucket list. His parents are hoping to raise £2,500 through a fund dedicated to the young boy, Happy Memories and Wishes Fund, so he can enjoy the rest of his life to its fullest.

View the slideshow to see photos of Oliver and Helen Mirren.