Campo, 28, passed a medical and agreed personal terms after meeting club officials on Friday evening.

Bolton are now waiting for international clearance to arrive.

However, Campo will not figure in Sunday's match against Aston Villa because he is short of match fitness.

Campo has been a long-term target and manager Sam Allardyce is delighted to have him on board.

"It has been a long haul but we have been patient as always and resilient as usual," said the Bolton boss.

"We haven't got as much as most in terms of finance but in the end we have managed to strike a deal, which is fantastic.

"We have had many disappointments over the last few weeks and, when you finally clinch one, it doesn't half cheer you up."

Campo joins an experienced squad with the likes of World Cup campaigners Youri Djorkaeff and Jay-Jay Okocha arriving in the summer.

Bolton have got off to a poor start and go into the match against Villa on the back of two defeats.

Allardyce added: "Campo is a good all-round defender. He is very strong, very quick and good in the air."

Turkish midfielder Akin Bulent has been cleared to play for Bolton after Galatasaray were ordered to give international clearance.