"Olympiacos is a challenge for me. I know I will be here for two years," Leto told the club's official website. "I've had two weeks of pre-season training with Liverpool and I believe I will be ready to do whatever I have to.
"Olympiacos are a great team who challenge for every honour in Greece and in the Champions League.
"The team has some good players, a well known coach and fanatical supporters which always inspires them."