The story that Gene Roddenberry would have you believe (and the one we propagate with this profile) is that he added Walter Koenig as Checkhov in Season 2 of Star Trek to satisfy the cries of Russians everywhere that they, the pioneers of space, ought to be included in the crew. It's not true.
Koenig was added to try to bring in young female viewers with someone who looked like (frightening to comprehend now) teen idol Davy Jones of the Monkees. This is confirmed by William Shatner in his book. Did it work? Considering the show was cancelled after Season 3, we're gonna say no.
That leaves us with only one question: What teen idol does Anton Yelchin look like? Glancing at the picture above we're going to have to say....none.
Anyway, Yelchin was suggested by Olivia from Winnipeg. Thanks Olivia!