The 21-year-old winger emerged as an Albion target on Sunday - with the Express & Star exclusively reporting that the club had made a loan bid for the England under 21 star.
It comes after they lost winger Tom Fellows in a £10m move to Southampton on Friday.
It was expected Albion would add a winger to the squad - and they are now set to land their man.
A season long loan deal was agreed yesterday between the two clubs - and now a medical will take place with the deal set to be complete on transfer deadline day.
It will see the former Juventus man become Albion's eighth summer signing - but just their second loanee after Toby Collyer arrived from Manchester United earlier in the window.
Iling-Junior will come in as another winger option for Albion - but someone who also brings versatility having featured at left back for Middlesbrough during a loan spell last season.
The England under 21 man did spent last year out on loan at both Boro and Bologna. It came after he made the switch from Juventus to Villa last summer.