Forsaking her stilettoes would have brought her rangy 5' 11" frame closer to Cruise's 5' 7" and lowered the potential for hilarity during their on-screen romantic clinches. McGillis still complains that she can't watch the film, convinced her appalling posture makes it obvious she's hiding the height difference.

"I was trying to be the incredible shrinking woman during that film, " she said in an interview last year. "I'll see a little clip of it on TV and the difference now is obvious."

But Cruise would appear to have grown an incredible several inches in the intervening two decades. According to sections of the UK media, untroubled by the risk of being labelled size-ist, the official wedding shots from last weekend in Italy showing Cruise as being slightly taller than his 5' 9" bride Katie Holmes are a case of mission impossible.

And a woman can only adopt a knees-bent gait for so long, as we know.

Remember Nicole Kidman's joy on her divorce from Cruise in 2001? It wasn't about getting the car or the kids: "At last I can wear high heels again, " she said with one of her trademark, heartfelt gasps.

Kidman and Cruise's relationship began when they met on Days of Thunder and in 1992 they costarred in Far and Away. Fitness expert Pat Henry, who organised work-outs for Cruise when he was here to make the film, recalls that the Hollywood star was barely 5' 7". But he didn't avail of the special stretching exercise programme at Henry's Dublin studio.

"It's possible, through exercise, to add an inch or two to height. We get quite a few people who have applied to the Garda Siochana, but don't qualify for the height requirement . . . some have been refused for being as little as oneeighth of an inch too short. We've devised a programme that involves putting on gravity boots and hooking, upside down, onto an exercise bar and then going through a number of stretching exercises to open up the spine, lengthen the neck and position the head correctly. A lot of people you see out on the street walk with their head shot forward . . . good posture can make an enormous difference. Walking straight, with head held high, makes people look more graceful . . . and taller."

It's said that Cruise wears lifts in his shoes, which could explain that suspiciously late growth spurt.

'Elevator shoes' (all over the internet from just $59.99), put a whole new meaning on the phrase leather-uppers. Manufacturers claim that height can be increased by up to four inches with 'discreet' shoe lifts. A number of Hollywood names are said to have reckoned that a clod-hopper gait is a small price to pay for that extra stature.

Irish menswear fashion designer Nicky Wallace doesn't know about elevator shoes, but says bespoke, made-to-measure tailoring can rectify any perceived short-fall in terms of physical appearance. He's also supportive of Cruise, saying that the notion that a man should be taller than his female partner is very much old hat anyway.

"You see guys in Italy who are smaller than their woman companion and it doesn't matter. People here can be very conservative.

A lot of below-average height men do wear higher heeled shoes and boots. Bono (5' 6") does it, and I'm sure Tom Cruise does it as well.

But it's not such a terrible thing." It doesn't always do to meet your hero in the flesh, though, says Wallace, who has discovered that some stars are shockingly titchy.

"I remember meeting Kris Kristofferson, he of the deep, gravelly voice, some years ago . . . and couldn't get over how small he was."

If Cruise has got taller, his star quality has been slightly in the descendant since he appeared on the Oprah Winfrey show, declaring his love for Holmes by jumping around on the sofa like a flea. His subsequent proselytising for Scientology by describing psychiatry as a 'pseudo science', and then suggesting vitamins could cure post-natal depression raised more than Brooke Shields' hackles.

Cruise's lack of charisma, as opposed to inches, is what seems to draw so much criticism from the media. Because when it comes to the height debate, force of personality makes up for a lot. Little Alan Ladd (5' 5") had to carry his orange box from set to set, but stars like Humphrey Bogart (5' 8") and James Cagney (5' 5") carried around a tough-guy image that transcended issues of size. The problem for so many male actors is that their fellow female professionals are, often as not, drawn from the world of fashion modelling. And there are only so many men to whom 5' 10" Charlize Theron, or six foot Uma Thurman, have to raise their gaze. Katherine Hepburn, who at 5' 7" always wore high heels and a high hair-do to challenge intimidating Hollywood moguls, was nonetheless anxious about meeting fellow actor Spencer Treacy for the first time.

She greatly respected the older, and only very slightly taller, star, but was worried that she would tower over him.

"Don't worry, " said director George Stevens. "He'll soon cut you down to size."

But what of the film career of wonderful Kelly McGillis? It sounds as if she still hasn't recovered from appearing in a Tom Cruise movie.

"My posture sucks in that film. I hate it so much I can't watch it."

We have a little hunch you're right Kelly. But sometimes you have to stoop to conquer.