Oscars 2015: Is John Travolta's touchy-feely style inappropriate?
Just as it seemed John Travolta would redeem himself for last year's Oscars social faux-pas, he made the Academy squirm all over again.
After getting Idina Menzel's name completely wrong in 2014 ("Adele Dazeem") the Grease star took the stage alongside the US singer to mock himself for his error.
He got her name right this time. But then began stroking and clutching her face in a creepy manner from which the Frozen star appeared to recoil.
Earlier on the red carpet Scarlett Johansson turned away in apparent disgust as Travolta reached a palm around her waist and appeared to rub her body.
They weren't the only ones feeling uncomfortable.
"Travolta leans in, grosses out" said the Boston Globe, while the Evening Standard dubbed it "the most awkward moment of the Oscars".
The Telegraph's film critic Robbie Collin went further, saying the encounter with Johansson "sums up sexism in Hollywood".
So where exactly is the boundary between a fond embrace and a slimy invasion of privacy?
And in the touchy-feely world of Hollywood, is there any excuse for the Saturday Night Fever star's over-friendly fingers?
According to etiquette guru Liz Brewer, there is no public setting in which Travolta's behaviour would be deemed charming or acceptable.
"The Oscars is a dignified event. There is a way to behave. You are on screen, doing your job and representing your trade.
"What was he trying to do? Steal the limelight? I would have been appalled.
"I don't know how well he knows Scarlet Johansson, but that is inappropriate - totally unnecessary."
In any professional setting "touching someone else, in any way, is always a big deal" says Daniel Post Senning, of the Emily Post Institute.
"We say the heart of good etiquette is making other people feel at ease. You have to have empathy.
"But look at the reactions [to John Travolta]. Idina Menzel can't yell out 'Stop!' because she's on stage. So when she starts to pull away from him, he needs to be aware of that.
"I'm reminded of when George W Bush tried to give Angela Merkel a back rub [at the G8 summit]. She just winced and shrugged him off."
The comfortable distance in public in the US is "about 18 inches" says Senning. Any time you venture closer than that, you have to be very clear what the rules are.
"We advise that a handshake is always safe. But if you're going to do a social hug then if at all possible make eye contact first - let them know you're coming," says Senning, who co-hosts the Awesome Etiquette podcast.
Another useful guideline, he says, is to "give yourself the gender test".
"Professional etiquette is gender-neutral - so try to treat everyone the same. Would John Travolta stroke the chin of a man he's presenting with?"
US Vice-President Joe Biden was criticised last week for letting his hands linger on the shoulders of Stephanie Carter, wife of new US Defence Secretary Ashton Carter.
"But I'm not sure Joe Biden would go up to a male staffer, grab his back and whisper in his ear," says Senning.
Another rule: "Think about your intention". What are you trying to communicate by your gesture?
"With Idina Menzel it almost seemed like Travolta was trying to grab her attention - by literally pointing her face into his eyes.
"But we tell clients not to touch their own faces. So someone else's face is definitely off limits."
There's an awkward expression, he says, for people who behave like Travolta - "being a bit handsy."
And remember, he says, bad social etiquette doesn't just affect the person you're talking to. The effect on the witnesses - in this case a worldwide TV audience - is often as dramatic as the victim themselves.
"There is only one piece of news that penetrated my social media this morning - John Travolta," says Senning.
"So be careful how you greet people in your workplace. Otherwise, the next day, you might end up as the trending topic."