The details of the deal with the player himself, for example how long Ashton's contract will be, have yet to be revealed for the £7.25million transfer.
Hammers Chief executive Paul Aldridge, however, believes the move represents value for money for his club in securing a player who has suddenly begun to draw comparisons with Alan Shearer, and who will compete with the likes of Marlon Harewood and Bobby Zamora for a place in the Irons line-up.
"Alan Pardew has identified Dean as a player who can play a key role in helping the club to reach a new level, and we have therefore worked extremely hard to ensure that the transfer goes ahead," said Aldridge of the former Crewe man.
"We are paying a club record transfer fee for Dean because we feel that, at 22, he represents an investment that can benefit West Ham for years to come at the highest level."