Jack Black is annoyed at actor Chris Hemsworth after watching 'Thor: Ragnarok' and discovering that they used the same Led Zeppelin song that was used in 'School of Rock'. They are now embroiled in a social media feud known as the 'Battle of the Jams'.

Jack Black at Ping Pong 4 Purpose eventJack Black at Ping Pong 4 Purpose event

Of course, there's nothing serious about this beef. But Led Zeppelin are a band of whom it is notoriously difficult to get permission to use their music, and Jack had to practically beg them to let him sing 'Immigrant Song' in his 2003 movie 'School of Rock'. 

Since then, the song has also been used in 2007's 'Shrek the Third', but Jack only has a vendetta against the creators of 'Thor: Ragnarok' and spoke about his fury (pretend, obviously) about them 'stealing' the 'raddest part of [his] movie' in a video on Instagram.

'It's come to my attention that someone kinda stole that chunk of our movie and put it in their movie. That's right; I'm talking about 'Thor: Ragnarok'', he said. 'Totally bit our style, totally poached our jam, and now they're parading around town like they thought of it! Well, you don't get to do that and get away with it, bro. I'm calling you out, Thor. This is a challenge. I challenge you to a battle. A Battle of the Jams.'

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Chris Hemsworth even responded to the comments in an Instagram video of his own, though pointed out that they never owned the rights to the song in the first place. 'You're right, you got me. Guilty as charged. We stole 'Immigrant Song' from you', he said. 'But guess what, you stole it too. And as Oscar Wilde once said, 'Talent borrows, and genius steals', so we're both guilty of the same crime.'

He also made a cheeky dig at Jack Black's own song 'Tribute', released by his band Tenacious D, adding: 'We would've used your song but, as you said in your song, 'This is not the greatest song in the world', so we moved on.'

As it happens, Chris doesn't actually understand the terms of this 'challenge' that Jack has set him. You challenged me to a Battle of the Jams. I don't know what that means', he said. I don't know what a Battle of the Jams is. I know what jam is - jam on toast? I love a bit of that. Bit of Pearl Jam? Awesome! And just general jammin'. So, yeah, let's do it. Whatever. My place or yours, baby. I'm in.'

More: Is Chris Hemsworth getting bored of Thor?

Luckily for him, Jack posted another video that appeared to give some kind of explanation. On the set of his forthcoming movie 'The House with a Clock in its Walls', he alongside director Eli Roth, co-star Cate Blanchett and child actor Owen Vaccaro acted out a slow-mo fight scene to the tune of 'Immigrant Song' which saw Jack indeed clutching a piece of jam on toast. He named the piece: 'Daddy's School Of Ragnaroth'.