Question: Are Adam Gontier and Björk both singers?

Context articles: Art of Dying (band)
Adam Gontier
Saint Asonia (album)
Benjamin Burnley
Saint Asonia
Big Dirty Band
Human (Three Days Grace album)
Riot (Three Days Grace song)
Björk
Three Days Grace

Art of Dying is a Canadian rock band fronted by Jonny Hetherington.
 The band is currently signed to Better Noise Records.
 Bassist Cale Gontier is the cousin of Adam Gontier, the lead singer of Saint Asonia and former lead singer of Three Days Grace.
 Prior to joining the band, Gontier and guitarist Tavis Stanley played in another band, Thornley.
Adam Wade Gontier (born May 25, 1978) is a Canadian singer, songwriter and musician.
 He is the lead singer, rhythm guitarist and main songwriter for Saint Asonia, but is best known as the former lead singer, rhythm guitarist and main songwriter of the Canadian rock band Three Days Grace.
 Gontier left Three Days Grace on January 9, 2013.
 In addition to his work with Three Days Grace, he has been involved in collaborations with other bands including Art of Dying and Apocalyptica.
Saint Asonia is the self-titled debut studio album by rock supergroup Saint Asonia.
 First announced via YouTube through a teaser in early May 2015, the first single "Better Place" was released on May 16, 2015.
 This also confirmed the group's lineup, with Adam Gontier as the frontman, Mike Mushok being the guitarist, Corey Lowery as the bassist and Rich Beddoe as the drummer.
 The album was released on July 31, 2015 through RCA Records.
 Gontier's uncle Tom Duffy provided the bass tracks for some of the songs from the album, while Lowery was hired afterward.
 This is also the only studio album from the band to feature drummer Rich Bedoe before he confirmed his departure in 2017
Benjamin Jackson "Ben" Burnley IV (born March 10, 1978) is an American musician, composer, and record producer, best known as the founder and frontman of the American rock band Breaking Benjamin.
 As the sole constant of the group, Burnley has served as its principal songwriter, lead vocalist, and guitarist since its inception in 1992.
 Since signing with Hollywood Records in 2002, Burnley has composed five studio albums under the name Breaking Benjamin, two of which have reached platinum and one of which has reached gold in the United States.
 Outside of Breaking Benjamin, Burnley has also collaborated with acts such as Adam Gontier and Red.
Saint Asonia (stylized as SΔINT ΔSONIΔ) is a Canadian-American rock supergroup originally consisting of former Three Days Grace frontman Adam Gontier (lead vocals, rhythm guitar), Mike Mushok from Staind (lead guitar), Corey Lowery from Dark New Day, Eye Empire, Switched, Sevendust, Stereomud and Stuck Mojo (bass, backing vocals), and Rich Beddoe from Finger Eleven (drums).
 In 2017, Beddoe left the band and was replaced by Mushok's Staind bandmate Sal Giancarelli.
 Formed in Toronto, Ontario, Canada in 2015 after Gontier's departure from Three Days Grace, they released their debut studio album "Saint Asonia" on July 31, 2015.
The Big Dirty Band is a Canadian supergroup composed of Rush's Geddy Lee (bass) and Alex Lifeson (guitar), Thornley's and Big Wreck's Ian Thornley (vocals and guitar), Three Days Grace's Adam Gontier (vocals and guitar), Die Mannequin's Care Failure (vocals) and The Tea Party drummer Jeff Burrows.
Human is the fifth studio album by Canadian rock band Three Days Grace.
 The album was released on March 31, 2015 through RCA Records.
 This is the group's first album without original lead singer Adam Gontier, and the first with former My Darkest Days lead singer Matt Walst.
 It debuted at No. 16 on the ""Billboard" 200.
"Riot" is the fourth and final single from the album "One-X" by "Three Days Grace".
 The song is about protesting against the negative things in life and was inspired by vocalist Adam Gontier's anger when he was in rehab for OxyContin addiction.
 The song was also featured in the video game "WWE SmackDown vs. Raw 2007" as an edited version.
Björk Guðmundsdóttir (] , born 21 November 1965), known as Björk ( ), is an Icelandic singer, songwriter, actress, record producer, and DJ.
 Over her four-decade career, she has developed an eclectic musical style that draws on a wide range of influences and genres spanning electronic, pop, experimental, classical, trip hop, IDM, and avant-garde styles.
 She initially became known as the lead singer of the alternative rock band The Sugarcubes, whose 1987 single "Birthday" was a hit on US and UK indie stations and a favorite among music critics.
 Björk embarked on a solo career in 1993, coming to prominence as a solo artist with albums such as "Debut" (1993), "Post" (1995), and "Homogenic" (1997), while collaborating with a range of artists and exploring a variety of multimedia projects.
Three Days Grace is a Canadian rock band formed in Norwood, Ontario in 1997.
 Based in Toronto, the band's original line-up consisted of guitarist and lead vocalist Adam Gontier, drummer and backing vocalist Neil Sanderson, and bassist Brad Walst.
 In 2003, Barry Stock was recruited as the band's lead guitarist.
 In 2013, Gontier left the band and was replaced by My Darkest Days' vocalist Matt Walst, who is also bassist Brad Walst's brother.