Are they? Aren't they? Did they? Didn't they? How could they? The gossip-sphere has been alive this week with rumours that big-faced X Factor boss Simon Cowell has declared his love for the one-time Baywatch babe Carmen Electra, with whom he'd flirted when she appeared as a guest judge on Britain's Got Talent earlier this year – and that she, in turn, has hinted that she may even want to have a child with the music mogul. But even before we'd recovered from this earth-shattering news, more cynical voices were already suggesting that the happy couple's liaison may not be all that it seems. Of course, it's early days, and we wish them only well – but it wouldn't be the first time that a romance has turned out to be a "showmance" (when two performers fall in love for the exact duration of the show in which they're co-starring) or even a "fauxmance" (when that relationship owes at least something to the powers of PR). In this case, we will just have to wait and see …
Michael Jackson and Lisa Marie Presley
Stop sniggering in the back. Though reports at the time suggested that the King of Pop's 1994 marriage to the daughter of "the King" put the sham into "shamone", Lisa Marie has always maintained that the relationship was real and passionate. He was, she insists, "very hot" in bed and, in 1995, she told the television interviewer Diane Sawyer that the rumours surrounding their marriage were "crap" and that she would never marry for any other reason than love.
Simon Cowell and Carmen Electra
"She's not my girlfriend," gushed the reality meister-in-chief, seemingly throwing cold water on the relationship even as it began last week – but no: he's saved it! "We're people who date." Boom! "TV Carmen dates Simon … and reveals she wants to be a mum," screamed the headline in Friday's Daily Mirror. Feel the love, people. You can see why they call him a soppy romantic, can't you? Anyway, he called the 40-year-old former dancer/Playboy pin-up/Baywatch babe "adorable", and she responded that he, too, was, wait for it … "adorable". You betcha! Have any two people ever been more suited? Only, don't go buying a hat for the wedding just yet, will you. Louis?
Verdict: The jury's out
Spencer Tracy and Katharine Hepburn
Voted the best on-screen lovers by the Royal Society of Chemistry, no less, the Hollywood duo synthesised in no fewer than nine Hollywood classics, from Adam's Rib to Guess Who's Coming to Dinner. Off-screen, meanwhile, passions were supposed to have run similarly high, with the pair allegedly enjoying a 26-year relationship, despite Tracy's refusal to divorce his wife, Louise Treadwell. But was their love affair the greatest myth of all? A recent memoir by Tinseltown tittle-tattler Scotty Bowers suggested so, adding to rumours that their relationship was merely a convenient cover for Hepburn's lesbianism and Tracy's bisexuality.
Verdict: The jury's out
Kim Kardashian and Kris Humphries
So in love were the American reality TV star and basketball player that the couple decided to broadcast their wedding last year in a two-part telly show. A mere 72 days later, Kardashian filed for divorce. "I'm committed to this marriage and everything this covenant represents," said a devastated Humphries. He countered by filing for annulment on grounds of fraud, claiming that the marriage had been undertaken as a publicity drive by his wife – which Kardashian denies. The embers of this scorching romance will smoulder on in court next year.
Verdict: The jury's out
Nick Clegg and David Cameron
It all started in a rose garden with misty-eyed glances and flirtatious badinage; truly, the tender coalition union otherwise known as "the Nick and Dave show" caused the nation's collective heart to swell on that fragrant spring morning back in May 2010. How stunned we all were, then, when the Pope declared himself Catholic and this special relationship transpired to be nothing more than a tawdry marriage of political convenience, rent asunder by arguments over AV, Europe and so on. When the inevitable divorce occurs, we only pray that neither party gets custody.
Robbie Williams and Geri Halliwell
Robbie and Geri, ex Take That "bad boy" and Spice girl-in-chief … a match made in tabloid heaven. The couple cavorted in the south of France in the summer of 2000, went skiing the following winter, and then Robbie gallantly suggested in a radio interview that he and Geri were friends who slept together occasionally. Geri got the hump and Robbie apologised for shooting his mouth off. Still, he said later, she was pretty annoying.
Henry VIII & Anne of Cleves
He was a rotund chicken-leg devourer with a penchant for the laydeez; she was a needlework expert who could speak only Low German and who was delivered with face fully wrapped. When they met, it was moider. Hang on, no it wasn't: the royal personage only divorced this one. When they met, Our 'Enry was reported to have said: "I like her not." Turns out she was clueless in the bedroom as well as being rather less beautiful than advertised. Old Tommy Cromwell was executed partly for setting up the couple, which says everything really.
Rock Hudson and Phyllis Gates
One of the industry's worst-kept secrets: Rock Hudson – every inch the hunky, chiselled-jaw, all-American romantic lead – was gay. But when the gossip rag Confidential threatened to reveal that Hollywood's most handsome bachelor remained single for a good reason, his agent Henry Willson moved fast to keep him in the closet. Willson struck a deal with the magazine, and Hudson was swiftly married off… to Willson's secretary, Phyllis Gates. They divorced, to no one's surprise, three years later.
Robert Pattinson and Kristen Stewart
They met at the auditions for Twilight, and the chemistry was soon working off-screen too … R-Patz and K-Stew were the ultimate showmance – until she cheated on him, to the insane wrath of teenage girls worldwide. They got back together earlier this year – just in time to promote the latest Twilight movie! This happy coincidence was not lost on commentators, who pointed out that they'd rake in more cash by presenting a loved-up front. Such cynicism about ones so young! We're sure the some-time vampires are still bitten'n'smitten.
Kylie and Jason
Those long hours spent on the set of Neighbours could lead to only one thing: sex in a Sydney Travelodge. But while her career soared, poor Jason was left nursing a broken heart – and though he has since spilled all in, first, an autobiography and then a Life Stories interview with Piers Morgan, Kylie has to this day kept her counsel on the matter. Still, they'll always have last Friday's "Especially for You" duet.