Harris overcame cancer in his first spell with Millwall
Southend have made their first signing of the close season with the arrival of 33-year-old striker Neil Harris from Millwall on a three-year deal.
Harris, Millwall's all-time top scorer with 138 goals, had a year left on his contract at the Den but made just 10 starts in 2010/11, scoring three goals.
He told the Millwall website: "I want to be playing week-in week-out.
"I am joining Southend for footballing reasons only and looking forward to the next chapter of my career."
The boyhood Southend fan has also played for Cambridge City, Cardiff, Nottingham Forest and Gillingham.
He told his new club's website:
"I have always said to my boy that you have to be respectful to the team I play for so I've always said he couldn't have a Southend shirt whilst I was at Millwall.
"I've talked him out of it but when I told him I was coming today to sign the first thing he said was 'can I have a kit' - I said of course he could.
"Would I have gone anywhere else? No, I don't think so. It is a lifelong dream to play here."