Fortune left Old Trafford at the end of last season

The 29-year-old South African has been training with the club after being released by United over the summer.

He played his second match for Bolton in the pre-season draw against Rangers and has impressed boss Sam Allardyce.

Fortune can operate either in central midfield or on the left and also played at left-back during his time at United.

He joined the Old Trafford club in 1999 for �1.5m from Atletico Madrid and made 76 appearances.

Fortune, who has been troubled by a long-standing knee injury, rejected a move to Celtic in June.

"Quinton is a player I have admired for a very long time, " Allardyce told the Bolton website.

"He is a quality performer with plenty of Premier League experience and he can play in a number of positions.

"He will be a very welcome addition to our squad."