How to watch: BeINSport has the match today. Fubo TV is a good place to get that channel in the US.
A bit of history: the photo below is the earliest one I’ve seen of El Madrigal (as it was then) and it’s from April 24, 1971, when Villarreal hosted Barcelona for the first time in what was then called the Copa Generalisimo, now the Copa del Rey. Villarreal won this match 1-0 but lost the return leg 2-0; Barcelona went on to win the trophy, defeating Valencia in the final.
In those days, La Liga only had 15 teams, so the season ended in April and the Copa followed it, ending in early July. Teams that progressed in the cup arranged friendlies to stay sharp.
In the photo you can see the big Quonset-hut like building behind the ground (demolished in the last couple of years to make room for an expanded plaza out front) and you can see the narrow side stand that runs along the Carrer Blasco Ibañez, though in those days there were fewer buildings and more trees on the other side of the road.
Here are the teams:
Villarreal: Asenjo; Mario, Álvaro, Funes Mori, Víctor Ruiz, Pedraza; Iborra, Morlanes, Cazorla; Chukwueze and Toko Ekambi.
Bench: Andrés Fernández, Bonera, Quintillà, Cáseres, Raba, Iván Martín and Bacca.
Barcelona: Ter Stegen - Sergi Roberto, Umtiti, Lenglet, Jordi Alba - Vidal, Busquets, Arthur - Malcom, Suárez, Coutinho.
Bench: Iñaki Peña, N. Semedo, Piqué, I. Rakitic, Messi, Prince y Aleñá.