Watching one of Alan Rickman's last films is "a lovely way to say goodbye" to him, Dame Helen Mirren said at the London premiere of military thriller Eye In The Sky.
Speaking on the red carpet in Mayfair, Dame Helen said she was feeling "incredibly sad" ahead of seeing Rickman on the big screen.
The Harry Potter star, whose last on-screen performance saw him play Lieutenant General Frank Benson in Eye In The Sky, died from cancer in January aged 69.
Dame Helen said: "It's incredibly sad to have to say goodbye to Alan, not least because he was far too young and he had such great work in him, ahead of him, as you'll see from his performance in this film, which is fantastic.
"The great thing is, it's very much Alan on the screen.
"It's not him playing one of his amazing characters - it's Alan as we all knew him and remembered him - so it's a lovely way to say goodbye."
The thriller sees her playing Colonel Katherine Powell alongside Rickman, her long-time friend.
Dame Helen was joined on the red carpet by actor Colin Firth, who produced the film, and Game of Thrones star Iain Glen.
Eye In The Sky is directed by Gavin Hood, who has also been at the helm of blockbusters such as X-Men Origins: Wolverine and Ender's Game.
Hood said the film was a "great thriller" that left audiences with "a great deal to talk about".
Also paying tribute to Rickman, he said: "He was so articulate, highly intelligent, funny, charming, warm - and he gives a fantastic performance.
"I had no idea when we worked - and I don't know that he did - that he was ill.
"It's just very sad for all of us that he's not here to talk about the film, because he felt very strongly about the themes and the ideas the film raises and he would have sounded far better talking about it than I would, with that beautiful voice."
He said Dame Helen's character was originally written for a man, but he "kept seeing Helen as this highly intelligent strong military intelligence officer" when reading the script.
"I thought that it would open the film up for discussion between men and women," he added.
On playing the military top dog role, Dame Helen said: "It's wonderful to play a woman in the military, and 10, 15 years ago I wouldn't have been able to play that role because there probably wouldn't have been women of that level in the military - and now there are.
"So there is a logic to it being a woman.
"The world of the military, and what the military have to do, is a very potent and important world, so it's great to have that available dramatically for us."
The film follows intelligence personnel who use drones to hone in on terrorists in a safe house in Nairobi, Kenya and discover an imminent attack is being planned.
When a nine-year-old Kenyan girl enters the kill zone, those watching are faced with the dilemma of how they should proceed.
It also stars Aaron Paul, who appeared in US series Breaking Bad as Jesse Pinkman - one half of the series' infamous crystal meth-concocting duo.
:: Eye In The Sky is released in UK cinemas on Friday.