Hewitt, 26, is currently ranked 21 in the world and has been without a coach since parting ways with Roger Rasheed in January.

The former Wimbledon and US Open champion will be hoping Roche can weave the same magic he brought to world number one Roger Federer, with whom he split before the French Open in May.

Hewitt said Roche would travel with him to all the major Grand Slams between now and the end of 2008, renewing a relationship that began when he was a teenager playing in the Davis Cup for the first time and Roche was team manager.

"He's a very positive guy, he's obviously one of the best coaches in the world," Hewitt told reporters.

"I'm really looking forward to renewing our partnership. We both know what we need to do to get on the top of the game again."

Roche said he would not have taken on the role if he doubted Hewitt's ability to regain the number one spot.

"That's the goal, I think we've got to shoot for the top," he said.

Roche said he planned to make minor adjustments to Hewitt's game.

"I think just a little bit more variety, not so predictable and also a little bit more aggressive," he said.

"Also, we'll be doing a lot of work on the serve."

Roche has previously worked with Ivan Lendl and Pat Rafter.