Politics is often described as show business for ugly people.
Few politicians can resist the lure of the flashbulb - or the opportunity to bask in a little reflected showbiz glamour.
By Brian Wheeler
BBC News Online political reporter
Joan Collins is the latest in a long line of stars to be pressed into action, to lend a much-needed touch of Hollywood to the mundane business of campaigning.
Give him a big hand...
But beyond securing a few extra column inches does celebrity endorsement ultimately do politicians - or their parties - any good?
PR chief Mark Borkowski, who has worked with everyone from Michael Jackson to Mikhael Gorbachev, warns there are potential "elephant traps" for all concerned.
"Celebrity endorsements are rarely plain sailing, full stop. You can make yourself more user-friendly by association with a famous person.
"But if that celebrity then chooses to behave badly, you are inevitably caught up in whatever mess they get themselves into.
"And unless you are courting A-list celebrities, there is also danger you will end up with has-beens."
For the politicians the attraction is understandable.
"Everybody is trying to get the same emotional connection as you get with Big Brother, Pop Idol or Fame Academy.
"Unfortunately, people are not as interested in politics as they should be," he adds.
British political history is littered with celebrity endorsements that have backfired.
Collins is among the list of famous supporters
It is not hard to imagine the delight of Young Conservatives in 1983, on booking Kenny Everett - then one of the biggest names on British TV - to appear at a youth rally.
The idea, presumably, was to add a bit of youthful sparkle, anarchy even, to an event whose other principal draws were old stagers Bob Monkhouse and Jimmy Tarbuck.
What they got, for their efforts, was endlessly replayed TV footage of a man with giant foam hands yelling "let's bomb Russia!," to loud Tory cheers, as Prime Minister Margaret Thatcher looked on.
Everett later said said he regretted the incident and that he had taken the foam hands to the rally because the Tories "asked me first".
But, for the party, the damage had been done.
A few years later, the Green Party scored a minor coup when it signed up an ex-BBC presenter to act as its national spokesman.
At that stage, David Icke was best known for presenting late-night snooker coverage.
The Greens probably wished it had remained that way, as Icke donned a turquoise shell suit and announced he was leaving the party - because he had discovered he was the Son of God.
"I think everyone in the party was genuinely shocked. There was no inkling this would happen," says Spencer Fitzgibbon, the party's media chief.
Big name signings
Icke went on to generate further controversy and was banned from speaking at Green Party fringe meetings.
But, once again, for the party, the damage had been done.
Rock and roll
"In the coverage, he was always referred to as a Green party spokesman, rather than a former BBC presenter or Coventry City's ex-goalkeeper," Fitzgibbon recalls ruefully.
The experience did not stop the Greens from courting celebrity support.
In the run up to 10 June elections, it has recruited Twiggy, left-wing comic Mark Thomas and gay rights activist Peter Tatchell, himself no stranger to controversy.
It claims to have more big name signings waiting in the wings.
But Fitzgibbon says the party says it has a less free-and-easy approach to its media presentation these days.
"The party has developed quite a lot in terms of professionalism since 1991. We do run a tighter ship these days. We are very careful in our handling of celebrities."
Even supposedly media-savvy New Labour has had its fingers burnt.
At the 2001 general election, the party screened a party election broadcast featuring Geri Halliwell serving tea to pensioners.
It later emerged the former Spice Girl was not even registered to vote.
But what about the celebrities themselves?
In his book, The Last Party, author John Harris chronicles New Labour's flirtation with Britpop and the birth of "Cool Britannia".
In one telling passage, he describes Damon Albarn, of Blur - in 1995 just about the hottest band in the UK - enjoying a gin and tonic with then leader of the opposition Tony Blair and John Prescott in the House of Commons.
Rock and roll
Mr Blair, who as a student briefly entertained his own rock star ambitions, reportedly greeted Albarn with the immortal line "So what's the scene like out there?"
The self-congratulatory mood was only soured, according to Harris, when Alastair Campbell, predictably wary of the fickleness of celebrity endorsement, asked Albarn: "What if you turned round and said Tony's a wanker?"
It was a prescient remark.
The Blur singer would go on to become one of the music world's most vocal Blair critics and a leading anti-war campaigner.
But in the run-up to the 1997 election, the idea of Mr Blair as the first rock and roll prime minister seemed plausible, Harris argues.
"It is perhaps hard to believe now but in the mid 1990s Tony Blair was seen as youthful, dynamic and idealistic, almost a John F Kennedy figure.
"He was even being described as "sexy", which is unheard of for a politician".
From the stage at the Brit awards, Noel Gallagher, of Oasis, hailed the Labour leader as the only man - outside of members of his band - "giving hope" to the youth of Britain.
He would later be rewarded with a visit to Downing Street.
But Labour's flirtation with the stars of pop and fashion was, ultimately, all about "photo opportunities," Harris argues, and those involved quickly began to get the feeling they were being used.
"It wasn't a relationship which amounted to very much.
"In the context of the 1980s and Red Wedge, when people like Paul Weller and Billy Bragg made it a condition of their support that they had some sort of leverage over youth and cultural policy."
It is also impossible to sustain any kind of rebellious stance while supporting the party in government, he adds.
"People realised pretty quickly that it would not be free guitars for all.
"Cool Britannia was finished by the hard realities of government."