Slovenian group JG3O, formerly Jarc Gregorin Trio was founded in 2016 by Jaka Jarc (with his father Matjaž Jarc (composition, bass, backing vocals) and former Sfiltrom band member Blaž Gregorin (drums). In 2017, the three-piece, along with guest musicians Maša Golob (violin), Chris Elphic (Guitar), Nina Škrjanc, Simona Plešic, Melisa Spruk (backing vocals), arranged, recorded and released the band's first album, the bilingual "There & Back Again" [Tja in spet nazaj].
Matjaž bowed out to focus on his classical composition yielding the bass to Janez Moder, a founding and continuous member of the acclaimed Slovenian progressive etno-rock ensemble Moonlight Sky.
In 2018, the band was joined by a fourth member, academic violinist Ana Mezgec. The group was no longer a trio nor limited to band members with the last names Jarc and Gregorin, and consequently adapted the name to JG3O.
The band re-released the album featuring new parts recorded by Ana Mezgec, Blaž Ogrič, and Janez Moder.