Up until now he has been portrayed as the cool executive with a heart of steel.

But an exclusive clip from Iron Man 3 shows that Tony Stark, played by Robert Downey Jr, has a change of heart following the devastating events that occurred in The Avengers.

Realising that life will never be the same again, Tony’s relationship with Pepper Potts (Gwyneth Paltrow) steps up a notch as he reveals she is now his number one priority.

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Struggle: Tony Stark turns to Pepper Potts for support in exclusive clip from Iron Man 3

Speaking in the emotional clip Tony says to Pepper: ‘You experience things and they are over and you can’t explain them.’

He continues: ‘The only reason I haven’t cracked up is probably because you moved in, which is great. I love you. I’m lucky.

‘But honey I can’t sleep. You go to bed and I come down here, I do what I know, I tinker.  Threat is imminent and I have to protect the one thing I can’t live without. That’s you.’

Tough: Robert Downey Jr’s character has a lot to come to terms with in the new film

Iron Man was last seen in the 2012 film The Avengers, when he teamed up with Captain America, the Hulk and Thor to stop Thor’s adoptive brother Loki from subjugating Earth.

But fans of the Marvel films will know that things didn’t go quite according to plan for the superheroes.

At the end of the film as they rallied in defence of New York City they soon realised they would be overwhelmed as wave after wave of Chitauri descended upon Earth.

The one thing: Tony tells Pepper that she is the one thing he can not live without

Vow: He tells her that all that matters now is protecting her

After intercepting a missile Stark’s suit ran of power and he fell back through the portal but fortunately the Hulk saved him from crashing to the ground.

Now realising that the threat is so much bigger than he ever thought the exclusive clip shows a previously unseen sensitive side to Tony.

Unsurprisingly he is left traumatised by the events that happened in New York and opens up to Pepper about how he is feeling.

Understanding: Pepper embraces Tony offering him the support that he needs

Recognising that things will never be the same again he tells her that she’s his number one priority and he needs to think about her now.

This is of course quite a change of heart from the Tony fans of the film are used to and a massive shifting point in their relationship.

And his vow to protect her couldn’t have come at a better time as super villain The Mandarin, played by Ben Kingsley, threatens her and his best friend James Rhodes (Don Cheadle) as he unleashes a new campaign of terror.

Concerned: Pepper is moved by what Tony is telling her if not a little surprised by him being so open

Speaking at the recent London premier Robert told reporters he enjoyed wearing the Iron Man suit for the third film in the series.

‘I can’t say if wearing the (Iron Man) suit gets easier but… we had a great time. We shot most of this movie in North Carolina and we had the best summer there,’ he added.

The 48-year-old actor has thus far refused to confirm if he will make another movie in the successful franchise but director Shane Black is confident Robert will return for at least one more outing as Tony Stark/Iron Man.

Iron Man 3 opens in UK cinemas on April 25 and in the US on May 3

No rest: He reveals he is unable to sleep while dealing with what has happened