Midfielder Jose Peleteiro Ramallo has left Celta Vigo to sign a three-year deal with Brentford.
Ramallo, who featured four times for the La Liga side's first team, arrives for an undisclosed fee, and manager Mark Warburton believes that he will improve the quality in his first-team squad.
Warburton is quoted by BBC Sport as saying: "Jota is a very talented left-sided player. He is very highly regarded in Spain.
"He offers us real technical craft, an attacking threat and excellent set-piece delivery. He adds another level of quality to the squad."
Brentford began life in the Championship with a 1-1 draw against Charlton Athletic last weekend.