Tore arrived at the Boleyn ground this morning to sign his deal and is likely to be unveiled shortly as a West Ham player.
The Hammers have agreed to pay a loan fee in the region of £5 million with a future buyout clause worth £13 million that the initial fee will be subtracted if Tore is signed on a permanent deal.
Tore arrived in London yesterday to undergo his medical which he passed and all that remains is for West Ham to unveil their new signing.
West Ham boss Slaven Bilic has been targeting Tore since last season. Tore has already played two seasons under the stewardship of Bilic during his time in charge of Besiktas.