The filming of the movie kicked off in Los Angeles on April 1, co-star Chris Evans, looked on as Johansson delivered her knock-out blow dressed in an army jacket, black trousers and knee-high boots, the Sun reported.
The 28-year-old actress has dyed her hair red for the film, and also appears to have lost some of her famous curves for the role.
Her Black Widow character in the film will join forces with Captain America, who has woken from frozen ice in the present day, to stop a powerful enemy hiding in Washington.
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