Constantine was released by Brentford in August

He verbally agreed the deal on Friday before scoring the equaliser at Scunthorpe at the weekend.

Constantine has scored four goals since arriving at Roots Hall after Brentford let him go at the start of the season.

The twenty-five year-old will stay at Southend at least until the end of the current campaign.

"I am really happy to have signed and now I've got to get my head down and try to do the right things," said Constantine.