West Ham United have agreed a fee of £20million plus up to £4million in add-ons with Stoke City for Marko Arnautovic on the day that the Premier League club has also signed goalkeeper Joe Hart on a season-long loan from Manchester City.

West Ham are also close to signing Javier Hernandez from Bayer Leverkusen with the Mexican striker understood to have settled on personal terms with the club. A fee of up to £13million has been mooted for Leverkusen to sell the ex-Manchester United forward who is keen to return to the Premier League.

If, as expected, West Ham sign Arnautovic, Hart and Hernandez to add to the free transfer of Pablo Zabaleta, who was allowed to leave City after his contract ended, it would represent a hugely successful transfer window for the club and manager Slaven Bilic who is determined to add more experience and personality to his squad.

Arnautovic has emerged as Bilic’s number one transfer target with Stoke City having rejected two bids for the Austrian international before agreeing an offer which amounts to £20million in cash up-front with an extra £4million depending on West Ham’s qualification for the Europa League.

Hart meanwhile said of joining West Ham: "I've always loved the club. I think you'll struggle to find anyone, apart from the direct opposing fans around London, who doesn't love the club. It's got something about it, it's got a lot history and I've always loved playing against West Ham.