The 30-year-old will join the Rhinos from NRL side Penrith Panthers ahead of the new Super League season.
Leeds director of rugby Kevin Sinfield said: “Once we became aware of Zane’s availability, he was our number one priority to strengthen our squad for next season and we are delighted to get the deal done.
“I would like to thank Penrith Panthers for their co-operation to complete the move.
“We have got an exciting crop of young players coming through at the Rhinos and to add a current international with a proven track record of winning will give our group a tremendous lift. We look forward to seeing Zane in blue and amber in 2021.”
Tetevano, who has featured in two of the last three NRL Grand Finals, is keen to test himself in a new environment.
“My personal motto is that I like to be challenged and this move is the next challenge for me,” he said.
“I have had my time in the NRL and had some amazing opportunities and been part of some incredible teams.
“I am excited to be coming to Leeds. I have been doing my research on the history of the club so I have an emotional connection with the highs and lows of being a Rhino.
“I played some of the big guys from Super League with New Zealand against Great Britain and some of those guys are absolute beasts. I am keen to test myself against them on a week to week basis.”
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