Downey Jr knocked 'out cold' in 'Sherlock' fight scene

Hollywood star Robert Downey Jr needed medical attention on the set of new Guy Ritchie movie 'Sherlock Holmes' - when he was knocked out by a giant wrestler.

The 'Iron Man' actor was filming a fight scene with seven-foot-tall co-star Robert Maillet when the big man threw a punch that left Downey Jr "out cold".

A nurse on set attended to the star and gave him six stitches in his mouth.

A source said: "Robert was accidentally caught on the chin by a thundering hook. He went flying and was out cold.

"He didn't want to go to hospital and kept trying to get up. He's a trooper."

But Downey Jr's condition wasn't the only issue director Ritchie has had to contend with - the movie has reportedly been plagued by various other setbacks.

One incident on Friday left the cast and crew running for safety after a petrol tanker burst into flames during a delivery to the set, closing down production for two hours, according to The Sun newspaper.

And the mishaps have prompted speculation the movie, which also stars Jude Law, is cursed.

The insider added: "There have been lots of other problems too... The crew have started joking about the curse of Sherlock Holmes."