Primarily a batsman, Pietersen also bowls some useful off-spin

The South African-born 24-year-old left Nottinghamshire after four seasons and had also been linked with Kent.

"I believe Kevin Pietersen is the most exciting prospect on the county circuit," said Hampshire's Australian captain Shane Warne

"He is a real match-winner and a welcome addition to our great squad who will fit in with our guys beautifully.

Pietersen is set to make his England debut on tour in Zimbabwe in November.

He is the third recruit in a week for the newly-promoted county, following former Notts colleague Richard Logan and Zimbabwean all-rounder Sean Ervine.

Warne continued: "As well as strengthening our batting, his off-spinners will be an added bonus.

"I was very impressed with him when we played each other and I am very excited to have a player of his quality join us at Hampshire.

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Pietersen recently completed a four-year qualification to play for his adopted country. He performed successfully on an England A tour to India last winter.

Hampshire manager Paul Terry added: "I am delighted that we have picked up a player of Kevin's class, the explosive batsman that I feel we have lacked and one who is capable of turning a game on its head very quickly.

"He is ambitious and hungry to succeed and the England selectors have already shown how highly they regard him."