Arnautovic joined West Ham from Premier League rivals Stoke in the summer of 2017 for an initial transfer fee reported by The Guardian to be worth £20 million.
The 28-year-old, who can operate as a forward or as a winger, moved to the Potters from Werder Bremen in the summer of 2013 for a transfer fee reported by BBC Sport to be worth £2 million.
The Austria international was a success during his time at the Potters, and he has explained why Stoke fans hate him.
Arnautovic told The Sun: “Stoke fans hate me because I was their favourite and I left.
“I never did anything bad towards them but they love their club so they turned against me, I understand that.
“It would be a shame if Stoke were to go down because they were a top ten club and we never had to fight relegation when I was there.”
Big game tonight
Arnautovic will feature for West Ham in their Premier League game against Stoke at the London Stadium this evening.
With both the Hammers and the Potters in danger of getting relegated to the Championship at the end of the season, the game is going to be huge for the two teams.
Arnautovic has scored nine goals and provided four assists in 22 Premier League starts for West Ham so far this season.