The X Files' David Duchovny has joined Michael Douglas and Russell Brand by announcing he's a sex addict, but does the condition actually exist or is it just an excuse to play away? Experts give their opinion on the addiction that's still sneered at.
What do David Duchovny, Russell Brand and Michael Douglas have in common?
It might not be quite what you think - as well as being on the celebrity A-list, they have all admitted they have a problem with sex addiction.
Many were shocked when X-Files star David Duchovny announced that he was getting treatment for being a sex addict - not least because he has a beautiful wife, actress Tea Leoni, and two children, Madelaine West, 9, and Kyd Miller, 6.
But celebrity gossip aside, Duchovny's revelation has also opened up the debate as to whether sex addiction really exists.
Dr Simon Kelly, consultant psychiatrist at celebrity rehab centre The Priory, says that even academics disagree on the subject.
Kelly explains that there are two different classification systems used in the US and in Europe. Sex addiction was previously recognised as a condition in the States, but now neither system includes it.
The debate in the medical world comes from whether it's just a form of human behaviour or an actual medical condition.
However Kelly insists a person can be addicted to sex in the same way that others are addicted to alcohol or drugs.
"If you think of addictions, it's a psychological compulsion. For example, to use a drug or engage in behaviour despite the harm that often sits long after the physical symptoms of withdrawal has abated; people have a compulsion to do stuff. There are addictions such as gambling, which is already classified, so I think it's just that the legislators of us as psychiatrists are a bit behind the times."
Kelly also says that sex addiction can be proven medically.
"We've got a reward system in the brain which releases something called dopamine," he explains.
"It's released when we do something that's pleasurable, challenging or exciting. So if you go out and buy a pair of Jimmy Choo shoes, gamble, engage in sexual behaviour, or have alcohol or drug use you get a lot of dopamine being released.
"For the majority of us who don't take recreational drugs, probably the most stimulating experience that we do is a sexual experience.
"Now, clearly, if you can get dependent on any other type of behaviour you can get dependent on sex as a behaviour as we release dopamine so we feel good about it. Between one and six per cent of people have a problem with sex behaviour and a problem with in terms of frequency or social consequences of the behaviour."
This may be so, but many still believe these so-called addicts should just exercise some good old-fashioned self-control.
It's easy to look at a celebrity - like Duchovny, Douglas or Brand - and think that they have chosen to 'out' themselves as sex addicts rather than admit they've been caught cheating.
However Kelly disagrees - claiming there are three clear rules that define a sex addict as opposed to someone who's just been caught with their pants down.
"The three core features of a sex addict are firstly, they have shown a loss of control, whether that's using inappropriate partners or just showing compulsion to be involved with someone sexually.
"The second is the continuation of the behaviour despite adverse consequences, this relates to the risk taking, for example dating when one's away from home, engaging in behaviours despite the consequences, i.e if my girlfriend finds out this is going to be a disaster, the person continues.
"Finally the third feature is they get withdrawal symptoms when they stop it. With sex addiction this tends to be feeling anxious or depressed - this is when it goes back to the biology of dopamine - where you only feel good when you're engaging in this behaviour."
But is it just an addiction for celebrities? It's rare that you'll come across an ordinary member of the public who'll admit they are a sex addict. Even Kelly agrees that one of the most notorious examples of a sex addict was the powerful leader Gengis Khan, who had hundreds of children.
While Kelly admits that celebrities have the added allure of fame and money - and therefore more access to sexual partners, he disagrees that the average person won't become addicted.
In fact, the prevalence of sexual content available on the internet now means people don't even need to be sexually active to become addicted, he says.
"If you look at the internet, the most common search entry is sex and something like 40% of men have looked at pornography in the last month, which is pretty staggering.
"What happens is they then get into a cycle where that behaviour is rewarding because of the dopamine. Viewing pornography then becomes habit-forming, a solitary behaviour which is associated with masturbating. They're also getting visual material, so the internet is causing a lot of problems with sex addiction."
While celebs are no more susceptible to sex addiction than the rest of us, men are more likely to become sex addicts than women, Kelly says.
"Men can get sexual arousal pretty quickly from a visual stimulus but for women, generally speaking, it's about forming a relationship where sex is part of it," he explains.
"While divorce rates are going down, 70% of women don't cite sex as a reason for the break-up but the lack of an actual relationship."
If you're suspicious that your partner could be a sex addict, Kelly has a few words of advice.
He warns that you should look out for excessive internet use, or your partner being overly protective of their phone.
Sex addicts often have a chequered relationship history with a sequence of partners.
"It's a sign they are charming but it's flawed and what they tend to do is promise a lot, engage in people and then just move on."
As for poor Tea Leoni, should she stand by her man?
Kelly believes sex addicts can change and learn a new pattern of behaviour, but the risk of relapse is ever-present.
"It's like wanting to learn how to play an instrument - you've got to practice," he says.
"It's the same for changing behaviour. You've got to practice new ones."
CELEBRITY SEX ADDICTS
:: David Duchovny: The actor entered rehab for his sex addiction problem. In a strange case of life imitating art, Duchovny has recently played a sex addict in raunchy TV series Californication.
:: Russell Brand: As well as drug and alcohol addiction, comedian Russell Brand entered rehab for sex addiction in 2005.
:: Michael Douglas: He may be happily married to Catherine Zeta Jones now, but the seasoned actor has admitted to being a sex addict in the past. He checked into rehab in Arizona for treatment during his first marriage.
:: Eric Benet: The singer's problems with sex addiction were rumoured to cause problems in his marriage to actress Halle Berry - the pair split