“She found the truth about the character”: Downton Abbey executive producer Maggie Smith | Maggie Smith

AAs I read the various drafts of Julian Fellowes' pilot script for Downton Abbey, it was not lost on me that his new invention of the Dowager Countess (not yet cast) bore some resemblance to Lady Trentham in Robert Altman's film Gosford Park.

This film was in many ways a precursor to Downton. My original suggestion to Fellowes was to expand the premise of Gosford and reconceptualize it as a weekly episodic show. When it looked like ITV would actually greenlight the series, we turned our attention to casting.

Almost the entire cast came to audition before being offered the role, but there was no question of asking Maggie to come over or recite a few lines for us – that would have been rude and inappropriate.

The role of Violet Grantham certainly wasn't intended for Maggie – she had never appeared in a long-running TV series before, so I had little chance of getting it. But once we got to the site, it became very clear that it was her and we had to do our best to find her. For reasons I can't quite remember, she agreed.

I think she knew, as I did, that Fellowes was the finest illustrator in this rarefied world and that they could work well together. Ultimately, her contribution to Downton Abbey is immeasurable and the show would not have been the global success it has become without her.

As she read, she greeted me warmly because it wasn't our first time at the rodeo. By chance I went to school with her sons Chris and Toby. Chris and I were contemporaries, Toby a few years younger. Chris and I started working together at the Chichester Festival Theater the day after we left school. We did our best to build sets for what was then a studio theater – a marquee. These sets all fell apart. But it was a start and we loved it.

We loved her performance because she recognized the truth of the character and was never ashamed to deliver those hard-edged lines, no matter how archaic or antediluvian they sounded. Of the many aphorisms and “zingers”, everyone remembers the rather brilliant “What's a Weekend”, but she caused a stir with less remembered ones Bon mots such as her rejection of Lady Sybil's claim that she was political: “No. She won’t do that until she’s married, then her husband will tell her what she thinks about it.”

She wasn't remotely like Violet – except that she was a woman devoted to her family. But she understood Violet. When you're working on a screenplay, a character is just words on a page and just an idea, a template for what they could be. It wasn't until we saw the scenes she played perfectly that we got to see one of our greatest movie characters come to life.

A favorite scene? When the widow hears the news of her granddaughter's death, she arrives at the abbey. As always, she had a steely presence, but for once there was a chink in the armor as she braced her arm on the wall to steady herself, even though she knew she could actually collapse at any moment.

As was well known, she did not tolerate fools. In an earlier film from the 1990s I made the mistake of having a very casual first day with no dialogue. On the second morning, she strolled past me and muttered, entirely for my benefit, “All I have to do on this show is walk up and down fucking hallways.” She might be an intimidating presence to anyone, but I can attest to the fact that the entire cast and crew of “Downton” across six seasons and two films, had the honor of working with this hugely consequential star on stage and screen.

She was particularly close to the actors who played the other family members. But I always felt admiration for the other actors in the company who she really admired, like Jim Carter and Phyllis Logan. What I remember most is her great generosity and affection for the three young actors who played her granddaughters. She loved all of her scenes with Michelle Dockery, Laura Carmichael and Jessica Brown Findlay and enjoyed seeing them fly earlier in their careers.

The last Downton film revolved around the death of the Dowager Countess and will now be particularly poignant for her Downton friends and family. I'm so glad we came up with a fitting ending for such a remarkable film character. As she left the set for the final time, the cast and crew lined up in front of the abbey and applauded her as she was wheeled into her car. She had the privilege of witnessing this brilliant film character brought to life by this immensely talented yet private individual.