The former Southampton striker made the move before the World Cup.
"My first reaction at the time (when my agent rang) was something along the lines of 'get lost'," said Lambert, referring to the phone call that turned his world upside down in May. 'I didn't believe him at first. When I got out of bed properly and listened I realised it was genuine.
"But now I have to get picked, progress with the club and impress the manager. That's what matters. Obviously when I look back over my career I'll never forget my time at all my clubs who mean a lot to me, but I'm thinking I have to think about what I do from now."
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