Celtic are reported to have paid a loan fee of £432,000 for Junior Adamu.
For £4.3m a permanent deal has been negotiated with Freiburg for the summer.
Celtic announced the signing of Adamu just after 6pm on Transfer Deadline Day.
With Tomas Cvancara making a promising start and Kelechi Iheanacho back from injury Martin O’Neill will have some striking options in the weeks ahead.
ADDING ADAMU
News emerged on Sunday afternoon about Celtic’s interest in Adamu, followed quickly by O’Neill confirming that medicals were underway.
Celtic never made any permanent signings during January but money was spent to bring in the Austrian striker.
Adamu will be expected to train with his new team-mates this morning ahead of Wednesday’s match at Aberdeen.
Over lunch Martin O’Neill will host a media conference where transfer activity and reaction will dominate.
Despite a lack of game time Julian Araujo and Cvancara have come into Celtic and made an instant impact.
Adamu hasn’t had any playing time since December 20 but has been involved in the Freiburg squad until January 25 when he was on the bench against Cologne.
Cvancara started and scored against Falkirk on Sunday with Iheanacho playing the last 10 minutes off the bench.
With Celtic struggling on the right-wing there is the prospect of reverting to playing two strikers, the favoured system of O’Neill when hewas manager more than 20 years ago.
Celtic face constant midweek matches over the coming weeks including Europa League matches against Stuttgart.
Three changes can be made to the Europa League squad. Adamu, Araujo and Cvancara look like being included with Johnny Kenny, Callum Osmand and one other dropping out.
Celtic face Stuttgart on February 19 and 26 with two strikers brought in from Bundesliga clubs added to the squad.