Celtic secured the signing of Olivier Ntcham for a fee that wouldn't have looked out of place during Martin O'Neill's glory days at the club, as Brendan Rodgers hoped to piece together a squad capable of competing in Europe.
Seventeen years have passed since the Bhoys last broke their transfer record, and while they have done excellent business in selling, including the £11.5million they received from Southampton for Liverpool transfer target Virgil van Dijk, they have kept the purse strings tight.
Big money doesn't guarantee success, as some of the names on the list below will testify, and Celtic have always been great at spotting a bargain.
Henrik Larsson signed from Feyenoord for £650,000 and Ľubomír Moravčík, although 35 years old, became a hero when he joined from Duisburg in 1998 for £300,000.
The likes of Alan Thompson, Stillian Petrov and Maciej Żurawski just miss out, but how well do you know the players who Celtic went big on in the transfer market?