Jay became Albion's first signing of the summer 2017 transfer window when he signed a four-year contract following his transfer from Southampton for an undisclosed sum.
It was a deal Baggies Head Coach Tony Pulis was delighted to complete having twice before been frustrated in his efforts to sign the Burnley-born forward.
He had spent a frustrating final season with the Saints while still managing five goals despite making just nine starts.
But there were never any doubts football would be his game, his Spanish father Enrique (Kiko) once having been on the books of Deportivo La Coruna.
Jay duly made his breakthrough at his home town club, signing pro for Burnley in 2006 and developing his game with loans in Scotland before revealing his potential with a wonder goal against Nottingham Forest.
He top scored for Burnley in the 2011-12 season which would be the prelude to a transfer to Southampton, scoring his first Premier League goal in the October of that first campaign against Spurs.
Already an England Under 21 representative, Jay received his first call-up to the senior squad and made his debut against Chile in November 2013, finishing that same season as Saints' top scorer on 15 goals.
He was a contender for the England World Cup finals squad that following summer but his progress was jolted by a knee ligament injury from which he spent the following year recovering.
But declaring himself fully recovered, he started last season with a goal which saved Southampton from a home defeat against Sunderland.