Celtic have won the race to sign Wolves striker Kenny Miller on a pre-contract agreement.
The Scotland international will join the Bank of Scotland Premier League leaders in the summer on a three-year contract, with Celtic having the option of a further year.
The former Rangers and Hibernian star, who will cost Celtic nothing as he is out of contract this summer, said: "It is a tremendous honour to have signed for a club of Celtic's stature."
The Wolves frontman held talks with the Bhoys yesterday about a move.
But Miller's agent David Baldwin revealed Celtic faced stiff competition from a number of Italian Serie A clubs as well as from the English Premiership.
The 26-year-old, previously of Celtic's arch-rivals Rangers and Hibernian, is out of contract at the end of the season and has rejected offers of a new deal from Wolves.
Celtic manager Gordon Strachan has been left short of attacking options with the departure of Chris Sutton and an injury to youngster Craig Beattie.
It had been thought Miller was keen on being given another chance to shine in the Premiership, having suffered relegation to the Championship with Wolves.
But he appears likely to join the SPL leaders and become one of the few post-war players to have played for both sides of the Old Firm.
Alfie Conn played for Rangers then Celtic, via Tottenham Hotspur, in the 1970s.
Fellow forward Mo Johnston, more controversially, joined Rangers in 1989 from Nantes after publicly saying that he was looking forward to a second spell with Celtic.
Miller moved to Ibrox from Hibs for £2million in 2000 but struggled to make an impact with Rangers and was sold to Wolves for £3million 18 months later.
Celtic are also thought to be closing in on Debrecen winger Peter Halmosi.
