Katy Perry will be temporarily replaced on ‘American Idol’ while she is in Britain for King Charles’ coronation. The ‘ET’ singer, 38, and fellow judge Lionel Richie, 73, are set to take to the stage at Windsor Castle in London on 7 May for the king’s coronation show, and a couple of “big time” stars are set to fill in for the pair. Their co-judge Luke Bryan, 46m told Entertainment Tonight about the stars who will fill the pair’s seats when they are away: “It’s big time.