Wolves striker Kenny Miller has signed a pre-contract agreement to join Celtic in the summer.
The 26-year-old former Rangers player has been given a three-year contract, with Celtic having the option of a further year.
Miller, who has scored four goals for Scotland this season, said: "I was fortunate enough to have options.
"But, when Celtic made their interest known, this was where I wanted to play. It's a tremendous honour."
Miller, who has also played for Hibernian, had rejected a new contract at Molineux.
Rangers had been linked with bringing the player back to Ibrox and there was also interest from Italian clubs.
It had been thought Miller wanted a move to the English Premiership, but he is now eager to join up with manager Gordon Strachan.
"Having spoken to Gordon and the club, I am delighted to have committed my future to Celtic," he said.
"I am looking forward immensely to joining my new team-mates in the summer and hope to be able to play my part in bringing further success to Celtic.
"Clearly, my focus for the rest of this season is Wolves and I will be doing all I can to assist the club in its efforts to secure promotion from the Championship."
Miller will become one of the few post-war players to have performed 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 to sign for a second time to Celtic.
Miller spent four years in the green and white of Hibernian before moving to Ibrox for £2m in 2000.
He struggled to make an impact with Rangers and was sold to Wolves for £3m 18 months later.
But Strachan said: "Kenny is a quality player and I am delighted to have secured his signing for next season.
"He is still a young player with his best years ahead of him and I am sure he will be a great addition to our squad from next season onwards."
Celtic chief executive Peter Lawwell added: "There were a number of other clubs trying to sign Kenny.
"We are delighted to have won the race and signed Kenny on a long-term contract."