But why exactly was I there? Had I taken regression therapy which demanded that I return to the stage of a 13-year-old autograph-hunter? Well, no, I was there to observe Lynam finally grab the limelight he deserves and become a movie star.
Lynam out-cools anything this side of the Arctic Circle. As the BBC's premier sports presenter, he has carved a reputation as more unflappable than a chicken with no wings. Neil Morrissey, his co-star in the film, reckons that "a bomb could explode underneath him and he'd say: 'Sorry, there appears to be a bit of smoke'. He's the Elvis of sport."
With this image, it was only a matter of time before Lynam made the move into movies with the title role in My Summer With Des, written by Arthur Smith. So now he is sitting in the pub waiting for his close-up.
Smith was responsible for An Evening with Gary Lineker, about Italia 90 (is he praying England do well in the World Cup this summer so he can get another drama out of it?). In My Summer with Des, the writer has cannily cast Lynam as a divine, omniscient mentor - not unlike the Humphrey Bogart figure in Woody Allen's Play It Again, Sam. Des comes down from on high to advise the lovelorn Martin (played by Morrissey) on his affair with the angelic Rosie (Rachel Weisz). The whole thing is obviously tongue- in-cheek, but the writer has tapped into this latent sense of Lynam as a national treasure.
"In a crisis, you'd trust Des to look after things," says Smith. "He's a masterful presence - yet compassionate. He's an ideal deus ex machina. You can easily imagine him descending from the skies and sorting everything out.
"He also realises that sport isn't everything. He'd be fun over dinner - unlike the other sports presenters, who'd be nerdy. You get the impression that Des may have had a secret past; he might have run off and joined some Patagonian bandits in his youth and rescued a dizzy blonde. He has a witty quality. There's a touch of the writer about him. I remember him saying once: 'There's Leboeuf with his son, Le Spare Rib'."
The director of My Summer with Des, Simon Curtis, is also a card-carrying member of the Des Lynam Appreciation Society. "Those sporting events on the BBC like the World Cup, Euro 96 and Wimbledon do unify the nation. Des is a symbol of all that. He's our MC. After the penalty fiasco and Gazza crying against Germany at Italia 90, Des said "and those of you going out tonight, go out with peace in your heart". He has a kind of Churchillian rhetoric that elevates an event. People perceive him as a god-like figure." I wasn't in the least surprised to hear a continuity woman on set singing "there's only one Desmond Lynam".
For Weisz, who has starred with Keanu Reeves and Vincent Perez, "Des has more charisma than practically any actor I've come across. He's got movie-star eyes and that slow-burn, smouldering quality. He would be very good in a leading role. The main thing you need in films is charisma. Without trying, he's just got pots of it." Next stop, 007?
Sipping a whisky and water with no ice (the sports presenter's equivalent of a dry martini shaken, not stirred) in the snug bar between takes, Lynam is done up as suavely as we've come to expect: a natty blue admiral's blazer and dark slacks, teamed with an official Euro 96 tie. In a typical flourish, the sobriety of the ensemble is subverted by a cheeky cartoon cat pattern on the socks.
The man himself plays down the image which had him described in one article as "the Jesus of Cool". "Me and the word 'icon' were not mentioned in the same breath till Chris Evans started using it - and then I had to go and look the word up. I don't deal with it, I just turn up and do the job. New presenters are always being compared to me - I don't know why, I've done some bloody awful programmes. All that does drive me slightly mad. You're not a live TV broadcaster for as long as I've been without going slightly cuckoo - as some of my predecessors have proven."
The film takes as its backdrop the ready-made drama of England's progress through the Euro 96 tournament, which climaxed in the thrilling - and ultimately heart-breaking - penalty shoot-out against Germany in the semi- final (again). As he signed off that night, Lynam pinpointed the mood of the nation: "You'd better remember where you were watching this tonight, because in 30 years' time someone will probably ask you." He had instinctively realised that this was a "JFK moment".
Lynam is able to send up gently the accolade of having his name in the title of a film. "It's been a long time coming," he snorts. "All my life, I've wanted a play named after me - now, of course, I've become very precious as a result, demanding better lighting and make-up. I have people scurrying around asking if I want a cup of tea every five minutes. Never get that in BBC Sport; they just throw the tea at you."
Smith says the screenplay is "A Midsummer Night's Dream meets An Evening With Gary Lineker", and Weisz reckons "that summer already has mythical status. Our fairytale slides together with it very easily".
It was a time when, for once, it wasn't embarrassing to be English. In Morrissey's eyes, "the feeling of Euro 96 was so electric. After all that crap about the dentist's chair in Hong Kong and Shearer not scoring for 12 games, it was a great boost. It's easy to forget how magical it was in England, to walk down the street and hear shouts from people's houses. It was like the VE Day celebrations over again".
And, according to Curtis: "The connection between England's football team and the psyche and confidence of our nation is extraordinary. Football allows people to express their emotions in a way that they can't at home. It becomes a shorthand for thwarted relationships and ambitions. We had got used to losing and to the dark days of Heysel, Hillsborough and hooliganism. Cool Britannia began with Euro 96. Suddenly we were proud to be British again.
"The last time football was this trendy was during the George Best era. Football is at the centre of this exuberant, Britpop, Men Behaving Badly culture. But the bubble might burst. You always knew that Harold Wilson was blessed by 1966. If France 98 isn't a success for England, it might signal the downfall of the government!"
Before I reel out of the bar, Morrissey reflects on his job. "How good is this? I get to drink with Des Lynam - and I get paid for it. I have to pinch myself sometimes." Hear, hear.
'My Summer with Des' is on BBC1 at 9pm on Monday 25 May.