Robert Downey jnr in <i>Iron Man 3</i>.

Suits you, sir: Robert Downey jnr will reprise his Iron Man/Tony Stark role in two Avengers sequels. Photo: Supplied

Anyone who stayed till the end of the credits at the close of Iron Man 3 – come on, film nerds, you know who you are – will have seen the bold prediction ''Tony Stark will return''.

Bold because Robert Downey Jnr had not yet re-signed with Marvel Studios to extend his run in the iron suit of the titular inventor-playboy-hero.

But now he has. Sort of.

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Marvel – which is owned by Disney – announced Thursday (Los Angeles time) that the actor had signed on for two more appearances as Iron Man/Tony Stark, in The Avengers 2 (to be directed by Joss Whedon and slated for release in 2015) and The Avengers 3.

The deal suggests that an Iron Man 4 is not in the works at this stage. And given that Downey Jnr will be 52 by the time The Avengers 3 appears in cinemas (ETA: 2017) that makes the likelihood of another outing in a standalone Iron Man film fairly unlikely.

The Hollywood Reporter claimed in early May that Downey's deal with Marvel could be worth between 5 and 7 per cent of the ''first dollar gross'' of receipts on any movie in which his character appeared. His cut from The Avengers (2012), which grossed more than $US1.5 billion worldwide, has been estimated at more than $50 million.

"Isn't that crazy?'' he told GQ magazine. ''They are so pissed. I'm what's known as a 'strategic cost'."

The cost to Marvel of Downey's star turn in Iron Man 3 isn't likely to be much cheaper: the movie has just passed the $1.2 billion mark worldwide.

Of course, Marvel could recast the role – and indeed may have to do so if they want the character to have the longevity of a Batman or Superman – but while Downey Jnr remains in the frame they will be hesitant to bet against him being the source of much of the attraction for audiences.

The figures don't lie on that front. On average, Marvel films gross an average of $404 million worldwide (according to boxofficemojo, and unadjusted for inflation). The four in which Downey Jnr has appeared have averaged $981.4 million each.

twitter: @karlkwin