Mel Gibson, who starred as Martin Riggs in the previous four parts of the 'Lethal Weapon' franchise, is set to direct 'Lethal Weapon 5' after the demise of director Richard Donner. During a recent event in London, Gibson said, "He (Donner) was developing screenplay...And he said to me one day, 'Listen kid, if I kick the bucket, you'll do it'."