Everything is also going full circle. On the Town's 1944 success marked Comden and Green's Broadway debut as authors and major-league lyricists, not to mention the first Great White Way appearances of the composer Leonard Bernstein and the choreographer Jerome Robbins. Forty-eight years on, here we are again, gathered together not only to applaud a prime example of seamless stagecraft - On the Town was and is a triumph of interlocking, complementary temperaments - but to celebrate a partnership that has lasted for more than half a century, perhaps the longest theatrical collaboration on record.
And what a partnership. Comden and Green - it's impossible to think of one without the other - flaunt legendary credits. Shuttling back and forth between Broadway and Hollywood they have written the lyrics, books or screenplays (sometimes all three) for Wonderful Town, Bells Are Ringing, Subways Are for Sleeping, Applause, On the Twentieth Century (stage), Good News, Singin' in the Rain, The Band Wagon and the astonishing, neglected It's Always Fair Weather, one of the most acidic, poignant musicals this side of Sondheim. If On the Town caught the desperate party mood of the Second World War ('Three sailors trying to live a lifetime in 24 hours,' comments Green), then the ironically titled Fair Weather captures the disillusioned mood of post- war slump: army buddies meet a decade after their glory days and detest one another.
'Oh, do you like it? So do we]' Comden laughs. 'It got great reviews but I don't think the MGM management understood, and audiences weren't going to musicals any more because of (withering pause) television. Also Gene Kelly wasn't the star he had been.'
'We did write it dark, definitely, definitely,' Green continues (the couple have an eerie habit of blending separate answers into a single stream of conversation). 'It's about the passing of time, friendship, disappointment. Fair Weather wasn't written to be up.'
'Actually,' Comden remembers, 'Fair Weather was to be our stage sequel to On the Town. We would have met the sailors 10 years later. We mentioned the idea to MGM and they said 'Give it to us.' So it never became the stage show we intended. Pity. It would have been good.'
It would certainly have been better than MGM's celluloid version of On The Town, which jettisoned the bulk of the Broadway tunes and went ruthlessly for leer, cheer and hyperactivity. 'Oh, a long sad story,' Comden agrees. 'The studio thought Leonard's 'symphonic' music was too obscure, that it wouldn't be popular. So they dropped, added, simplified. If only they had more faith in the score and in the undercurrent, which was meant to be bittersweet.'
In fact, despite a reputation for rhyming comedy patter and what the writer Mark Steyn has called 'fizz with froth and bubble', it's tempting to view the essential Comden and Green as bittersweet and, something more, as a discreet link between the confections of, say, Irving Berlin and the Worm-in-the-Big-Apple angst of Stephen Sondheim. No matter who writes the music, be it Jule Styne or Cy Coleman, running through their canon is a seam of blighted romanticism, a Big City sense of opportunities lost and loves vanished.
Urban jungle sophisticates wearing broken hearts on their sleeves, they began, aptly enough, in satirical revue, Greenwich Village-style (with Judy Holliday nee Tuvim), hoping to emulate the brittle anti-everything wit of the Algonquin Round Table. Common wisdom dictates that their second show, Billion Dollar Baby, flopped because the public wasn't ready for a musical about (of all things) the Wall Street crash. 'Baby was glamorous, and had chorus girls and a sense of fun, but it had this deliberate bleak side too,' Green shrugs. As did the disastrous A Doll's Life, a continuation of Ibsen's A Doll's House and a work wobbling wildly between genre imperatives - pretty people, lavish settings, happy endings - and rigorous observation of human foibles. Doll's run lasted barely a week.
In the partnership's best moments, however, those conflicting sensibilities magically mesh, although, instructively, it often takes a showbiz milieu or characters destined for lights, camera and action to facilitate the fusion: Fade Out, Fade In, Applause, On the Twentieth Century, Singin' in the Rain, The Band Wagon. A workable theory?
'Ah,' says Comden. Then, carefully, 'Let's say we don't like to theorise too much about what we do. But we certainly are conscious of what we do.' Which brings us to The Will Rogers Follies, currently wowing them on Broadway. 'It's a big, award-winning success,' Comden happily reports. 'It's part revue, part show and about an interesting man, a home- spun American star and philosopher. We're happy and proud because the theme is a man's character and what he meant to America.' Green clarifies: 'No spectacle for the sake of spectacle, no gimmicks, everything in the service of the show.'
A return to the musical's traditional values in other words. And a less than fond farewell to the technocrats who have recently dominated the form on both sides of Atlantic. Now mid-way through their seventies, Comden and Green have seen fashions come and go, surviving to witness their own enthronement as classics. The circle is complete: 48 years after On The Town hit the boards, the couple are back where they started - on top. Charmingly, they don't appear to have noticed. For suddenly Comden asks, 'When is this piece going in? We're doing our musical review, 'A Party with Betty Comden and Adolph Green', on Wednesday night and, well, we want to be sure people will turn up. They will, won't they?'
'A Party With Betty Comden and Adolph Green', 7.45pm, tonight, Barbican Hall, London EC1 (071-638 8891).