Ronny Deila stressed his desire to keep Fraser Forster at Celtic following the 4-0 victory over KR Reykjavik.
Executive vice-chairman Ed Woodward insists Manchester United are ready and willing to break the British transfer record.
Manager Kenny Shiels confirmed the Dutchman had passed a medical and signed on after rejecting an offer to stay in Paisley.
Shiels told STV: "We're really happy to get him on board because we've lost Ben Gordon so now we've got competition between Rory McKeown and Jeroen.
"I think there were a few teams in for him but we were in early, very early in fact and I think he was impressed with how we play and what we can offer him from a football perspective."
Shiels is still awaiting an answer from Farid El Alagui, who scored 29 goals for Falkirk last season, after offering the striker a contract.