Smith's co-stars Josh Brolin, Nicole Scherzinger and Alice Eve, along with director Barry Sonnenfeld, also walked the red carpet outside the Odeon Leicester Square as fans and photographers gathered to get a glimpse of the Men in Black cast.
Men in Black III sees Smith reprise his role as Agent J as he travels back in time to 1969 to save the life of his partner K (Josh Brolin). Tommy Lee Jones, Jemaine Clement and Emma Thompson are also among the cast for the movie, opening in cinemas on May 25.
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Photo gallery - Men in Black III premiere: