Julio César Villalba Gaona (born 17 September 1998) is a Paraguayan professional footballer who plays as a forward for Borussia Mönchengladbach.
Villalba signed with Borussia Mönchengladbach in January 2017.
Upon returning to Paraguay, he featured for Cerro Porteño U20 in the 2016 U-20 Copa Libertadores.
He made his first-team debuts for Cerro Porteño during 2016 and the club will enjoy little of him before the player departs permanently to the Bundesliga.
On 8 January 2020, Villalba was sent on loan to SC Rheindorf Altach of the Austrian Bundesliga for the remainder of the season.
Villalba featured in Cerro Porteno’s youth academy and Paraguay U17 alongside Sergio Díaz.
Villalba played at the 2015 South American Under-17 Football Championship, making 8 appearances.
He then featured at the 2015 FIFA U-17 World Cup making three appearances and scoring two goals against Syria U17 and France U17.