He was born in Barcelona (Spain) in 2005. Since 2019, he has studied with Professor Jens Peter Maintz in the Aline Foriel-Destezet Chair of Cello at the Reina Sofía School of Music. He also studies chamber music under Márta Gulyás and Heime Müller. He holds scholarships from the Banco Sabadell Foundation and the Albéniz Foundation.
He began his cello studies at the age of 6 and made his debut as a soloist at just 13, receiving an emphatically positive review that highlighted a sound “of impeccable quality and musicality” and an “interpretative ability with a very well-defined personality and independent judgment” that offered “a true lesson in maturity at the age of 13”. Since then, he has performed in some of Spain’s best-known halls, including the Teatro Monumental, among others.
He has won several awards, notably the overall prize at the MiN International Competition (Narvik, Norway) and first prize at the Certamen de Interpretación Intercentros Melómano. He has also received awards at the Bach-Wettbewerb and won the Primer Palau prize, as well as the Critics’ Prize and the Catalunya Música prize, in 2024, and second prize at the Tokyo Minato City International Music Competition, in 2025.
In recent years, he has also attended masterclasses with Lluís Claret, Pablo Ferrández, Asier Polo and Sol Gabetta, among others, and has been an invited student at the Cello Biennale in Amsterdam.
Guillem performed El Cant dels Ocells with Peter Thiemann on 26 August 2017 at the ceremony in memory of the victims of the terrorist attack in Barcelona.
As a student at the School, he has performed the Brandenburg Concertos with Sir András Schiff and the complete Goldberg Variations arranged for string trio; at the Gran Teatre del Liceu and the Auditorio Nacional de Música (as part of the Series La Generación Ascendente); with the Freixenet Orchestra (conducted by David Afkham, Andrés Orozco-Estrada, Péter Csaba, Sir András Schiff and Nicolás Pasquet), with the Camerata Fundación EDP (conducted by Paul Goodwin), with the School’s Baroque Ensemble (conducted by Paul Goodwin) and with the Sinfonietta (conducted by Johannes Kalitzke). In addition, in 2025 he performed with the School Orchestra at Carnegie Hall in New York under the direction of Andrés Orozco-Estrada. He has also been a member of the Satie de Bain and Lili Boulanger trios, the Ramales Quartet, and the Ambage, Tchaikovsky de Management Solutions and Scarlatti de Casa de la Moneda ensembles.
He plays a cello by François Caussin, Mirecourt, c. 1830–1840.