The one secret to Chris Hemsworth and Elsa Pataky's long-lasting marriage

They are arguably one of the most iconic power couples to come out of Australia in recent times – however, Chris Hemsworth and long-time love Elsa Pataky have worked hard to build and maintain their bond.

After only three months of dating, the pair tied the knot in a low-key Australian ceremony – and haven't looked back since.

Now, 15 years and three children later, the Thor star has opened up about the one secret that has kept their spark alive for all that time.

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Speaking to PEOPLE in a joint interview, Hemsworth, 42, and Pataky, 49, peeled back the curtain on their idyllic life in Byron Bay, revealing the key to their marriage, at the end of the day, is simple.

The pair credit the enduring success of their union to one thing; honesty.

"There's an honesty, the north star of truth, that you're going to get with Elsa. I can show something to a bunch of other people, and they might be like, 'Oh, great work,' but Elsa will tell me if it sucks," Hemsworth says.

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"I'll tell him, 'That's actually not funny. It doesn't work,'" Pataky confirms.

According to Hemsworth, this "critical sort of assessment" is a key to a healthy dynamic, where they both push one another to succeed.

The Crime 101 star says his wife's no-nonsense feedback tends to come in handy – particularly where matters of his A-list acting career are concerned.

"Elsa's honesty is my barometer for whether something works. I take that with the films I do, the commercials, whatever," he reveals.

"It's like everyone else can tell me one thing, but I know that I'm going to get the absolute truth from her."

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"And it's sometimes dressed up in gentleness from time to time, so that it doesn't shatter my soul, which I appreciate," Hemsworth says.

In a meet-and-marriage that typically spells 'doom' for Hollywood relationships, the superstar couple wed within three months of being set up by their agents in 2010.

The actor has been candid about the importance of communication within his relationship on countless occasions in the past.

First and foremost, Hemsworth has credited the success of their marriage to "fun."

He went on to say both "having an adventurous spirit, and making time for one another" was absolutely essential for a long-lasting bond.

"The complicated times have been when it's been all work, all kids, and all of a sudden the 'us' in the relationship is … sort of non-existent, you're just managing a household or the work family schedule," Hemsworth said.

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