Albian Ajeti has completed a medical at Celtic as the Hoops look to sign the Switzerland international on a permanent deal.
An initial loan move with an option to buy the West Ham striker for £5m has been agreed, but Celtic would now like to make an immediate permanent transfer.
Celtic's move for the 23-year-old, who only joined West Ham last summer, was in jeopardy two weeks ago when Ajeti asked for more time to consider his options while on holiday in Sardinia.
But Sky Sports News understands a personal intervention by boss Neil Lennon convinced Ajeti to choose Celtic, after a host of Premier League and European clubs were also interested.
Ajeti was a target for Sky Bet Championship side Brentford last summer but wanted to move to the Premier League from Basel, where he had emerged as one of the Swiss league's best strikers.
He had scored 37 goals for them but failed to register for the Hammers last season as he struggled for minutes under both Manuel Pellegrini and David Moyes, making a total of only 12 appearances.