According to The Guardian, the London outfit had to pay Besiktas a loan fee of £2.5 million to secure the services of the 24-year-old winger for the 2016-17 campaign.
It has also been reported that for West Ham to make the deal permanent next summer, they would have to pay the Turkish club a further £10m.
Tore has arrived at West Ham with a strong reputation and will be expected to hit the ground running.
The Turkey international winger worked with Hammers’ manager Slaven Bilic at Besiktas.
The former Hamburg and Rubin Kazan winger was on the books of Chelsea from 2009 to 2011 and featured for the London club’s Under-21 side.
West Ham fans have taken to Twitter to give their reaction to the signing of Tore on a season-long loan deal.
Below are some of the best comments:
Glad Tore signed for West Ham. Even I jumped the celebration gun tweeting early that he was a Hammer! #COYI— Mikespace Online ™ (@MikespaceOnline) July 11, 2016
@WestHamMatters Tore showed a lot of intent and we kept at it, quite impressive— Carter Southgate (@COYI_Carter) July 11, 2016
Gokhan will be the best Tore in the Premier League this year (I know the Toure bros. aren't spelled the same, but still). COYI. #WHUFC— Stutterin' Stan (@SSSelekts) July 11, 2016
Gokhan Tore confirmed! Another superb piece of business for the best owners in the Premier League #COYI— David Poacher Walsh (@DavidPoachWalsh) July 11, 2016