Real Madrid midfielder Thomas Gravesen has arrived in Glasgow for talks and a medical with Celtic.
The Dane left Everton for Spain in a £2.5m deal in January 2005, but following the appointment of Fabio Capello at Real, he has been deemed surplus to requirements.
Real president Ramon Calderon told the club website that an agreement had been reached to sell Gravesen.
A Celtic spokesman would only say that “talks (with Gravesen) are ongoing”.
Celtic view Gravesen as a replacement for Stilian Petrov who is expected to sign for Aston Villa before Thursday’s transfer deadline.