[1] Fonseca's musical career started with a band called Silence 4, formed by a group of hometown friends.

They first released the unpredictable Silence Becomes It, in June 1998 which was a huge success at the time, selling 250,000 copies (the equivalent to six platinum records).

Later in the same year, in December, Silence 4 was the first national band to sell out at Pavilhão Atlântico, performing to an astonishing 18,000-strong crowd, only 6 months after the release of their first album.

The respective tour ended in a double concert at the legendary stage in the Portuguese capital of Lisbon, the Coliseu dos Recreios, which sold out completely and was released later on in CD and DVD format.

In his first solo work Sing Me Something New, recorded in 2003,[2] Fonseca sang and played nearly all the instruments, exploring a totally new environment of sounds on his own.

The first single was Someone That Cannot Love which debuted on about 150 Portuguese radio stations in a coordinated release: they were all played on 10 March at midnight.

The tour supporting this first record was extensive; it included many big music venues and large festivals across Portugal.

Thus, the CD and DVD with the recorded Coliseums’ live concerts, which were released in November 2006, marked the end of the Humanos project.

He plays different instruments during the show and he is accompanied by his band, which includes: Sérgio Nascimento (drummer), Ricardo Fiel (guitarist), Rita Redshoes (ex-Atomic Bees in the piano and also voices; the second record single "Hold Still" is a David and Rita duet), Nuno Simões (bass player) and Paulo Pereira (Hammond).

He also plays (in most of his live concerts) "Angel Song", the first music he wrote, and composed when he was only 18 and which was included in Silence 4's first album.

In the middle of the show, he usually leaves the stage to return wearing a white suit, to announce that "dancing time" has begun and that the "moonwalk" move is near.

In 1999 he travelled to England to work with producer Darren Allison on the Phase song "City" from their album 52 Minutes of Your Time.