Celebrities usually know how to play the chat show game. You have a project to promote, you smile, say hi, get through a bunch of generic questions, then you've done your bit – if you can get "A Viral" out of it, say a dance routine or a lip sync battle, then you're golden.

But then there are those moments where stars unexpectedly go the extra mile for their promotional tour – whether the publicist intended it or not. Here are some of the 'greatest' eccentric chat show appearances ever where stars went totally off-piste…

1. Nicolas Cage throws money and karate kicks on Wogan

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Is this the greatest chat show entrance of all time? For us, there's no question. Before Cage was fully a household name, when he was peddling a little-known film from David Lynch called Wild at Heart, he made quite the impression on the UK with this incredible appearance.

The young and 'merry' star somersaulted his way onto the set, tossed cash at the audience, high-kicked repeatedly and then proceeded to remove his clothes mid-chat, with consumate professional Wogan no doubt wondering who the hell this weirdo from California was.

2. Drew Barrymore flashes David Letterman

Before she was the respected actress and activist she is today, Barrymore was the original wild child – and this was Drew at her headline-creating peak. In one of Letterman's most memorable interviews, she gave our Dave an impromptu dance number for his birthday, before quickly flashing him while standing on his desk. Letterman's fuzzy-eyed reaction says it all.

Speaking about it years later to Entertainment Weekly, Barrymore said: "From the moment I went on – especially with my little dance number, which was completely spontaneous and not calculated in any way — he let the audience know it was okay. He was so accepting of me, and letting everyone know to just go on the ride."

3. Tom Cruise jumps on Oprah Winfrey's sofa

So iconic it's become known as the 'jumping the couch' incident, Tom Cruise famously went full Maverick on Oprah, not able to contain his love for then-girlfriend and future ex-wife Katie Holmes.

In what was a PR disaster at the time, Tom's leap of love – followed, less well-remembered, by him dragging poor Katie on to the set from backstage – was one of the most cringeworthy chat show moments ever. (He was promoting War of the Worlds, not that you'd know.)

4. Grace Jones smacks Russell Harty for ignoring her

This is why chat hosts have their own chair and you don't place them in the middle of the guests – not only will someone famous end up feeling left out, but your master of ceremonies is within arm's length of a smacking.

You most certainly shouldn't try this interviewing technique when one of the world's greatest divas has stopped by. Grace Jones wasn't happy when then-king of chat Russell Harty kept turning to speak to his other guest, and she made sure he knew it by repeatedly whacking him.

5. Bruce Willis wears a meat hat on Letterman

Jaded Brucie tends not to be the most enthusiastic guy on the couch anymore. Catch him in any TV interview nowadays, peddling whatever mid-tier movie that's paying him this month.

But every now and then Willis shows that he still has a cheeky side, including this bizarre moment in which he wore a slab of meat on his bonce in tribute to Lady Gaga's infamous meat dress.

6. Oliver Reed gets totally plastered on Aspel

If you had the late, Oliver Reed on your show, you were guaranteed something different. However, watching this famous moment on Michael Aspel's show was half hilarious, half utterly depressing.

The Gladiator actor and then-alcoholic appeared on set, pint in hand, before giving a 'unique' performance with the house band. Apparently the producers thought it would be a good idea to send him on in this state.

7. Joaquin Phoenix is fully spaced out on Letterman

Everyone was concerned about Joaquin back in 2009, after he appeared unkempt and zoned out, declaring that he was retiring from the film business to pursue a hip-hop career.

It later transpired that it was all a hoax for his mockumentary movie I'm Still Here with Casey Affleck. Returning to the chat show in 2010, Letterman revealed that he had no idea it was all a stunt at the time. Now that's some serious commitment to your work.

8. Andy Dick feels up Ivanka Trump and gets removed by security

A truly awkward and horrible moment occurred on Jimmy Kimmel Live! in 2007, in which comedian Andy Dick went too far with his infatuation with Donald Trump's daughter Ivanka. Kimmel called in his security guards after Dick touched her legs, and they promptly dragged him off by his limbs.

Kimmel later said: "Andy did a segment, he was a little out of it. [When Ivanka] came out, he wanted a big, wet kiss. It was time for Andy to go, so I escorted him out by his feet. He always makes me a little uncomfortable, you have no idea what he's going to do next."

Come to think of it, has anyone seen Andy since Trump became President?

From: Digital Spy