The Wales international is reportedly closing in on a move to the Spanish side for a reported £85m, which will beat the £80m Madrid paid to sign Cristiano Ronaldo in 2008.
Gullit is quoted as saying by The Mirror: "Bale is going to take the transfer record past the €100million barrier, as soon as Real pay that amount into Tottenham Hotspur's bank account.
"I find this astonishing. This is a player who has not won a single thing in his career, yet he's becoming the most expensive player in football history.
"The pressure on Bale will be enormous because of the amount of his transfer fee and because it is Real Madrid. This transfer tells you everything about the incredible ambitions of Real Madrid.
"They are doing this with Bale because they are still annoyed that Brazil star Neymar was stolen from them at the last minute by arch-rivals Barcelona."
Bale reportedly arrived in Spain yesterday to secure his move to Madrid.