Mark Ruffalo was left super embarrassed and worried for his job last month when he accidentally live streamed the audio of the first ten minutes of 'Thor: Ragnarok' at the premiere after failing to properly end his live video on his phone. He spoke out about the incident on 'The Late Show with Stephen Colbert'.

Mark Ruffalo at the Thor Ragnarok premiereMark Ruffalo at the Thor Ragnarok premiere

The 49-year-old who plays the Hulk in the new movie had never used Instagram live in his life, and probably never would have if his bosses hadn't persuaded him to do a little backstage video ahead of the 'Thor: Ragnarok' screening. In other words, it was totally not his fault.

'In my defence, [Marvel / Disney] asked me to do an Instagram live post', he said. 'So I said I would do that but I've never done Instagram live so I didn't really know how it worked.'

He went on to explain just how the incident happened - in painful detail. 'I went backstage and I was doing the Instagram live and it was fun and games and everyone loved it, I was doing the audience and then they said, 'Return to your seat, we're gonna start the movie'', he continued. 'So I pushed the button which you think is going to stop it, but then there's another button to stop it. The first button just tells you to push the second button to stop it.'

Needless to say, the frustrating function left him with a red face when he was called out for streaming the film while in the screening. Though, of course, it being a movie theatre, he wasn't about to get his phone out to check what was going on with it.

'I ended up shoving it in my pocket and sitting down and watching the movie', he explained. 'It's broadcasting the movie basically free to millions and millions of hopefully paying viewers. And my phone was blowing up, people were texting me. I must've got fifty texts in ten minutes. But I didn't want to be rude and take out my phone and look at the texts. You can't do that in a movie! You're an a-hole if you do that!'

In fact, it was only when someone came up to him and explained the situation that he took his phone back out and sheepishly ensured the live video was ended. 'I'm sitting there enjoying the movie with my family and a woman came up and she poked me in the shoulder, and I turned and I said, 'What?' And she said, 'Your phone is on! You're Instagramming live this whole show! You've been Instagramming live for ten minutes! Turn it off!'

'People I haven't seen since high school are texting me!' He added. 'Turn off your phone, Marvel's gonna fire you!'

More: Mark Ruffalo streams 'Thor: Ragnarok'

Of course, it's very unlikely that he will be fired for such an honest mistake, but he's just completed filming on 'Avengers: Infinity War' so he'll know for sure soon. 'I went to bed a leading man and somehow I woke up a grandpa', Mark joked.