The move remains subject to Ferres agreeing personal terms and passing a medical.
Leeds chief executive Gary Hetherington is very pleased that a player of such pedigree has joined the Rhinos.
“We are delighted to have secured a player of the quality of Brett Ferres to complement our squad for next season,” he said.
“They know Brett and they are looking forward to having him within our group.
“We are fully aware of the challenge in front of us next season as we look to build on the achievements of last season and adding a player of international class like Brett is a major boost to our plans.
“I would like to thank Richard Thewlis and the Huddersfield Giants for the way they have dealt with the process and I am sure we have come to an arrangement that allows all parties to move onto the next stage and look forward to 2016.”
Leeds head coach Brian McDermott is glad that a competitor like Ferres is now part of his squad.
“We are pleased to have Brett on board,” he said.
“Our other three England internationals also return this week so he has not missed any of our pre-season preparations in comparison to those players.
“He is a tough competitor and someone I have admired for many years and it is great that the club have moved quickly to secure his services. He will immediately begin training with us with just four weeks to go until the start of the season whilst the terms are being agreed.”
Ferres, 29, added: “I would like to thank Gary Hetherington and Brian McDermott for making this move possible.
“The Rhinos are a fantastic organisation and I am looking forward to being part of the squad next season. The last year has seen plenty of ups and downs for me, however, this move gives me an opportunity to finally look forward to the future with confidence and be part of something special here at the Rhinos.”
Ferres will wear the number 26 jersey for the Rhinos.