Dame Judi Dench has revealed a very personal tribute to her friend and fellow actress Dame Maggie Smith, who died in September aged 89.

Dame Judi plants individual trees in memory of friends who have died and, on the day of Dame Maggie's funeral, her gardener found the sapling planted for her fellow acting dame had borne fruit.

"Joe, who works for me, came in and he had one little crab apple," Dame Judi told the BBC.

"And so I had it in my pocket at her funeral, which was a very nice thing to have," she said, in an interview recorded for the TV tribute Maggie Smith at the BBC, to be broadcast on 28 December.

The pair had been friends from the moment they first met in a dressing room at The Old Vic theatre in 1957.

Over the decades they worked together on both stage and screen, most notably in 1985's A Room With A View, 2004's Ladies in Lavender, The Best Exotic Marigold Hotel in 2011, and its 2015 sequel, The Second Best Exotic Marigold Hotel.

In a separate interview for the BBC's Lives Well Lived series, also to be broadcast on 28 December, mutual friend Charles Dance, who directed the pair of friends in Ladies in Lavender, describes how lucky he felt to have the celebrated duo as his leading ladies.

"I had Judi Dench and Maggie Smith - I could have shot the telephone directory with those two," he recalls.

"They just went for it. Little things like they're running up the stairs together, there's Judi trying to get up there before Maggie, and Maggie saying 'stop pushing me, stop pushing me!' That's all ad-libbed, you know. It was wonderful."

Dame Maggie Smith was famous not only for her impeccable comic timing but also for the caustic put-downs used with such stinging effect by characters including Downton Abbey's Lady Grantham and Harry Potter's Professor McGonagall.

Fellow Downton star Samantha Bond says fledgling performers in the series sometimes found it hard to distinguish between Dame Maggie and the acid-tongued dowager countess she portrayed.

"I think, perhaps, they got confused about whether she was the actor or whether she was the dowager…

"If she's just playing Maggie, then it's fun - it's real fun, with a lot of laughs," says Bond.

Dame Judi has the final word on her friend and ally: "Oh, she could be very scary. No question, she could be quite frightening. Get on the wrong side of Mags…

"But, oh, we had such good times.

"I have known her for a long, long time. Very, very funny and unbelievably witty and formidable.

"But a really, really sweet and special friend."