Rudolph made his debut for South Africa in 2003

The 25-year-old has been released from his contract with Cricket South Africa.

"I am very proud to be a Protea and to represent my county," he said. "This was not a decision to take lightly."

Yorkshire chief executive Stewart Regan said: "He has given us an undertaking that he will not seek to play for South Africa while under contract with us."

Rudolph, who has played 35 Tests, said: I discussed the matter fully with the management. We agreed this experience would be good for me."

The left-hander, who made 222 on his Test debut against Bangladesh in 2003, will play for Yorkshire under the terms of the Kolpak regulations.

These allow players from countries that have associate agreements with the European Union to enjoy the same employment rights as those born within it.

He is not currently part of the South African side, with Hashim Amla and Ashwell Prince preferred in the middle order.

"Obviously we are delighted to have signed a quality player such as Jacques for the next three years.

"He is a proven performer at the very highest level and we are sure his undoubted ability will add strength to our 2007 campaign," said Yokrshire's chief executive Stewart Regan.

"For Jacques to commit his future to Yorkshire proves beyond any doubt that will prove to our members and supporters that we are serious about competing in all forms of the game this season."

Pakistani batsman Younis Khan and Australian seam bowler Jason Gillespie will be the club's two official overseas professionals this summer, although Gillespie's compatriot Matthew Elliott has also been signed to cover while Younis is at the World Cup.

And the arrival of Rudolph adds further quality to a batting line-up which has lost Michael Lumb to Hampshire and may also be without Anthony McGrath, who has asked the club to release him from his contract.

"Cricket is a game where you have to learn and improve all the time, and I believe that playing county cricket for Yorkshire will give me new and valuable experience.