The Walking Dead - The Walking Dead: Season 2 - Episode 3: In Harm's Way
Didn't see anyone else post this (though if they did, sorry!) but Scott Porter tweeted that he recorded some lines for TWDG episode 3. Probably pretty obvious news, I myself had a feeling Luke would be returning but for those who thought he wouldn't until later, here you go.
(Doesn't mean he's alive though...maybe he recorded his death scene!)