HITC Sport understands that Norwegian has now put pen to paper on a pre-contract with the East London club.
Norwegian star Havard Nordtveit has put pen-to-paper for West Ham United, signing a pre-contract agreement ahead of a Bosman transfer in the summer, HITC Sport understands.
The Hammers have long been on the trail of the 25-year-old midfielder, who has spent the last six seasons with Bundesliga outfit Borussia Monchengladbach, but they have now secured his services - having decided not to extend Alex Song's stay at the club into next season.
Nordtveit has featured in nearly 150 games in Germany and has established him as a top-class midfielder, which lead to a host of clubs battling for his signature.
Clubs from Italy, Spain, France and Turkey as well as some of West Ham's Premier League rivals made approaches for Nordtveit - but he has agreed the terms of an initial move to the Olympic Park - where The Hammers will be playing when he joins - subject to him not picking up an injury before July 1, when he can sign officially for the club.
A source confirmed to HITC Sport: "The deal is done, and has been put to bed - both parties are happy to have got it done and finalised, of course an injury could still scupper the deal as a pre-contract isn't medical dependent but everyone is delighted to have got him."
The move sees Nordtveit moving back to London having joined Arsenal as a teenager from Haugesund. During his time with Arsenal, he never made a senior appearance although he did appear on the bench against Sunderland for the final game of the season in 2008.
After that point he spent time on loan at the likes of Salamanca, Lillestrom and Nuremberg before signing for Gladbach in 2008 when they paid 1million euros for his signature.