So Jim's body is actually Sam in Ghost Whisperer?

i recently started watching Ghost Whisperer, just the ones that come on during the day, i haven't seen them all. So, I saw a few episodes and Jim didnt remember who he was. So i looked online and it said Jims soul is in Sams Body. so Jim actually looks like Sam to everyone else in the series? and we see him as Jim because Melinda does?