The Baggies have agreed a fee with West Ham United for Diangana, who was on loan at the Hawthorns last season, and have been working to sign the player permanently.
However, Aston Villa and Fulham have attempted to insert themselves into the mix for Diangana, threatening to hijack West Brom’s swoop.
West Brom though look set to seal the signing of Diangana as, according to the Sun, the swoop now looks like a done deal.
Slaven Bilic’s side look to have beaten off competition to land the highly rated midfielder.
It has been claimed that the Premier League new boys are paying an initial £12m for the 22-year-old, with add-ons potentially taking the final fee higher.
Diangana helped West Brom to clinch promotion to the Premier League last season.
And Baggies boss Bilic is set to be able to count on the midfielder to help his side make an impact in the top flight.
