Robert Downey Jr. took on Jimmy Fallon last night in an infamous staredown on The Tonight Show.

Unlike Jared Leto, the Iron Man actor donned a long-haired wig as he sat atop a pretend mountain, sharing cryptic utterances like, “Osprey, I await. Prey upon my loins. Mount my torso like the bull of Poseidon.”

Though never one to go down without a fight, Fallon gave his best 'serious face' as he told of the tales each of the hairs on his body tell.

Our favourite is the 'almost sneeze' from RDJ, proving he really is quite the actor!

Earlier this week Kristen Stewart alsostopped by the show to talk her new movie Camp X-Ray, and while there played a quick game of 'Ring Around The Nosey'.

"It's so much better than looking sad!" the actress exclaimed as she donned a fetching elephant mask with trunk and all.

Robert Downey Jr.'s new film The Judge is set for release in the UK on October 10.