England midfielder Declan Rice says it has been a "tough" decision to leave West Ham but "it has only ever been about my ambition to play at the very highest level of the game".
Rice issued an open letter to Hammers fans as he nears a move to Arsenal for £100m plus £5m in add-ons.
West Ham also confirmed the 24-year-old was leaving the club.
"The last few days and weeks have been an absolute whirlwind of emotion," said Rice.
"I want you to know how tough a decision it has been for me to leave an environment that I have loved and cherished so much.