Smith was known for her roles in Harry Potter and Downtown Abbey, as well as her role in The Prime Of Miss Jean Brodie which landed her an Academy Award.
Her death was confirmed by her actor sons Chris Larkin and Toby Stephens, who released this statement.
"It is with great sadness we have to announce the death of Dame Maggie Smith", they said. "She passed away peacefully in hospital early this morning, Friday 27th September".
"An intensely private person, she was with friends and family at the end. She leaves two sons and five loving grandchildren who are devastated by the loss of their extraordinary mother and grandmother".
"We would like to take this opportunity to thank the wonderful staff at the Chelsea and Westminster Hospital for their care and unstinting kindness during her final days", they added. "We thank you for all your kind messages and support and ask that you respect our privacy at this time".
Following news of her passing, countless tributes were paid to the late Maggie Smith, including King Charles, Whoopie Goldberg, and her Harry Potter co-star Daniel Radcliffe.
"As the curtain comes down on a national treasure, we join all those around the world in remembering with the fondest admiration and affection for her many great performances and her warmth and wit that shone through both off and on the stage", King Charles wrote.
Whoopi Goldberg who starred alongside Smith in Sister Act, also shared this moving message via Instagram.
Daniel Radcliffe who starred as the titular character Harry Potter, also paid a sweet tribute to Maggie Smith.
"The first time I met Maggie Smith I was nine years old and we were reading through scenes for David Copperfield, which was my first job", he said. "I knew virtually nothing about her other than that my parents were awestruck at the fact that I would be working with her".
"The other thing I knew about her was that she was a Dame, so the first thing I asked her when we met was 'Would you like me to call you Dame?' at which she laughed and said something to the effect of 'Don't be ridiculous!'.
"I remember feeling nervous to meet her and then her putting me immediately at ease. She was incredibly kind to me on that shoot, and then I was lucky enough to go on working with her for another 10 years on the Harry Potter films".
"She was a fierce intellect, a gloriously sharp tongue, could intimidate and charm in the same instant and was, as everyone will tell you, extremely funny".
"I will always consider myself amazingly lucky to have been able to work with her and to spend time around her on set. The word legend is overused, but if it applies to anyone in our industry, then it applies to her. Thank you Maggie".
Harry Potter co stars Rupert Grint and Emma Watson also paid homage to Maggie Smith.
"When I was younger I had no idea of Maggie’s legend, the woman I was fortunate enough to share space with", Watson said. "It is only as I’ve become an adult that I’ve come to appreciate that I shared the screen with a true definition of greatness".
"She was real, honest, funny and self-honouring", she added. "Maggie, there are a lot of male professors and by God you held your own".
See more tributes below.
