Ramon Marcelino "Marc" Diaz Abaya (born November 3, 1979), is a Filipino singer-songwriter, actor, model, TV host, and VJ known for his work in alternative rock and television. He began his music career as a member of Shirley Beans before joining the original lineup of the alternative rock band Sandwich in 1998 as vocalist and guitarist, contributing to early albums such as Grip Stand Throw (1998), 4-Track Mind (2001), and Thanks to the Moon’s Gravitational Pull (2003). He left the band in 2005.
He later joined the rock band Kjwan, formed in 2003, and also worked as a video jockey for MTV Philippines. In addition to his music career, he has collaborated with artists such as Gloc-9 on the song "Tsinelas sa Putikan".
Abaya was a member of band Shirley Beans before becoming part of the original lineup of the alternative rock Sandwich in 1998 as vocalist and guitarist, alongside Eraserheads drummer Raimund Marasigan, Diego Castillo, Myrene Academia, and Mike Dizon. Abaya provided vocals on three of the band's early albums: Grip Stand Throw (1998), 4-Track Mind (2001), and Thanks to the Moon's Gravitational Pull (2003). He left the band in 2005.
Abaya, along with Dicta License bassist Kelley Mangahas and Boogie Romero, became a member of the rock band Kjwan, which was formed in 2003 and is known for its iconic track "Daliri." That same year, he also ventured into becoming a video jockey on MTV Philippines.
Abaya first appeared on television in the 2008 drama series Ligaw na Bulaklak as Francis, followed by the musical drama anthology Your Song, where he played Rafael "Raffy" Valero. He also became a host of a segment on the variety show It's Showtime, and later hosted Pilipinas Got More Talent, a spin-off program of the reality show Pilipinas Got Talent. In 2010, Abaya starred in horror film Dagim, for which he won "Best Supporting Actor" at the Cinema One Originals Awards.
In 2011, Abaya transferred to GMA Network to guest in the television variety show Party Pilipinas and to appear in the drama romantic comedy series I Heart You, Pare! as Joel. He played Gido in the action horror film Aswang. In 2012, he appeared in television drama series Faithfully, as Kevin Quillamor.
In 2019, he returned to ABS-CBN to appear in drama FPJ's Ang Probinsyano as Jacob Serrano, followed by action drama The Iron Heart in 2022 as Gaspar Kintanar, and drama Roja in 2025 as Lucas "Dos" Sebastian/Bishop Anthony.
In the 2026 ABS-CBN action-drama television series Blood vs Duty as Axl Rosales.
