John Hartson faces a sleepless night before discovering whether he has become Martin O'Neill's second summer signing at Parkhead.
The Coventry striker gave the Press a wide berth when he flew into Edinburgh this afternoon before driving down the M8 to Glasgow.
The clubs had already settled on an undisclosed fee earlier in the day and the 26-year-old quickly agreed personal terms before undergoing his medical.
However, before being whisked away from Parkhead tonight, he would only say "I'm hopeful" that he will finally become a Celtic player tomorrow.
A Celtic spokesperson confirmed tonight: "There are still a few things to be resolved, but nothing will happen until tomorrow now."
The Welsh international, however, faces an anxious wait as his scheduled Stg£6million move to Rangers collapsed a year ago after failing a medical.
However, his performances and goals almost saved the Sky Blues from relegation last season and the former Arsenal striker will hope that he has proved he is indeed fit enough to secure a move to Glasgow this time around.
Hartson's agent Jonathan Barnett, meanwhile, denied that Coventry goalkeeper Magnus Hedman was involved in negotiations.
"A fee has been agreed, but I've no idea how much that is, that's between the clubs," said Barnett.
"Hedman has not featured in these discussions, but you'll have to ask Coventry about that.
"Obviously John is very excited by the opportunity of playing for Celtic." -PA