Celtic have fended off competition from Charlton to sign Scotland defender Steven Pressley.
The 33-year-old's agent, Blair Morgan, revealed that Pressley opted to join the Scottish champions due to the promise of playing in the Champions League next season.
Because he played for Hearts in Europe this term, Pressley is cup-tied for the current Champions League competition.
Despite 33-year-old Pressley undergoing a medical with Premiership side Charlton on Wednesday, Celtic manager Gordon Strachan continued to talk with the player and his representative.
Pressley reached a deal to leave Hearts on December 9, six weeks after criticising the way the club was being run.
However rather than joining Charlton's battle to avoid relegation, Pressley will step into a Celtic team who have a 15-point cushion at the top of the Bank of Scotland Premier League.
Morgan told BBC Sport: 'It was a really, really difficult decision.
'He had two fantastic offers from two good clubs, but the lure of European football next season won the day.'
Pressley has signed an 18-month deal, keeping him at Celtic until the end of the 2007-08 season.
He cannot play until the new year, as the deal has occurred outside of the transfer window, but the centre-back could make his debut in the home match against Kilmarnock on January 2.
Celtic had urgent need for defensive reinforcements.
Bobo Balde has been ruled out for several months after breaking down against Dundee United on Boxing Day, joining fellow defenders Gary Caldwell and Mark Wilson on the long-term injury list.
Before Pressley's arrival, Paul Telfer, Lee Naylor, Stephen McManus and 19-year-old Darren O'Dea were Strachan's only fit defenders with first-team experience.