Beckham draped the overcoat over his left shoulder on the red carpet at the O2, London on Wednesday 22 February.
The 17-year-old also sported some new facial hair.
Beckham has had his left arm in a sling since he broke his collarbone during a family skiing holiday in Whistler, Canada on Saturday 18 February.
He shared a video on Instagram of the moment he sustained the injury while snowboarding.
He also shared a shot of his x-ray.