Chris Hemsworth attacks a punching bag while prepping for Thor's showdown with Hulk

The next Avengers movies won't be out until 2018 and 2019, but thanks to one of the movies' stars Chris Hemsworth, we may have just received a spoiler on what goes down in the upcoming sequels.

Look out, Hulk! Thor is definitely coming for you. You've been warned.

Chris, 33, hinted that Hulk might be taking a bit of a beating in the film in a video he shared with his 8.6 million followers. It racked up nearly 200k likes in just one hour.

In the video, Chris attacks a punching bag with gusto, not even letting up to catch his breath.

So what does that have to do with Thor v Hulk? Well, Chris captioned the video: "Getting ready to fight the Hulk".

Since this year's Thor: Ragnarok finished shooting last year, Chris must be in training for one or both of the Avengers movies.

Judging from his fast and furious pummelling, we're calling it. When Thor and Hulk come to blows, the green one had better practice an effective defence.

Mark Ruffalo, who plays Hulk in the Marvel films, appears to be more concerned with a different kind of fight in his recent Instagram posts, the one many Hollywood stars are waging against US President Donald Trump.

Alas, Mark's anti-Trump weaponry is limited to words. He's going to have pull out some heavier artillery to fight off Thor. May the best - and fittest - Marvel hero win.