Question: Are Billy Milano and Adam Levine both lead singers?

Context articles: Adam Levine
Something's Gotta Give (album)
Thrash of the Titans
Boomiverse
Billy Milano
Sad (Maroon 5 song)
M.O.D.
She Will Be Loved
Say It Again (Natasha Bedingfield song)
20 Years of Dysfunction

Adam Noah Levine (born March 18, 1979) is an American singer, songwriter, multi-instrumentalist, actor, and record producer.
 He is the lead singer for the pop rock band Maroon 5.
Something's Gotta Give is the fifth full-length studio album by New York hardcore band, Agnostic Front.
 It was released in June 1998 on Epitaph Records and follows 1995's "Raw Unleashed" compilation album.
 It is actually the first studio album since 1992's "One Voice".
 The album was co-produced by Billy Milano, the frontman of crossover thrash bands S.O.D. and M.O.D..
 It marks a return to a more hardcore punk style of sound than the thrash metal inspired music of "One Voice".
 Backing vocals, amongst others, were provided by Tim Armstrong and Lars Frederiksen of Rancid, and Jimmy Gestapo of Murphy's Law.
Thrash of the Titans was a benefit concert held on August 11, 2001 at the Maritime Hall in San Francisco, CA.
 The concert was a co-benefit for Testament vocalist Chuck Billy, who was diagnosed with germ cell seminoma (a rare form of cancer); and Chuck Schuldiner, leader of the death metal band Death, who was also battling cancer.
 The Master of Ceremonies for the evening was S.O.D. vocalist Billy Milano.
 The concert was organized by Walter Morgan.
 The show was announced in May 2001, and all 2300 tickets quickly sold out.
Boomiverse is the third studio album by American rapper and Outkast member Big Boi, released on June 16, 2017, through Epic Records.
 It serves as a follow-up to the rapper's sophomore studio album, "Vicious Lies and Dangerous Rumors" (2012).
 The album features guest appearances from Adam Levine, Jeezy, Killer Mike, Gucci Mane, and Curren$y.
 It contains production from frequent collaborators Organized Noise, DJ Dahi, Dr. Luke, Scott Storch, among others.
 It was supported by the release of two singles – "Mic Jack" featuring Adam Levine, Scar and Sleepy Brown and "Kill Jill" featuring Killer Mike and Jeezy.
Billy Milano is a Bronx-born heavy metal musician now based in Austin, Texas.
 He is the singer and - occasionally - guitarist and bassist of crossover thrash band M.O.D., and he was also the singer of its predecessor, Stormtroopers of Death.
 He was also the singer of United Forces, which also featured his Stormtroopers of Death bandmate Dan Lilker.
"Sad" is the ninth track from American band Maroon 5's fourth studio album "Overexposed" (2012).
 It was written by Adam Levine and James Valentine; they produced the song together with Noah "Mailbox" Passovoy.
 Valentine started composing the song on his home piano, before introducing the melody to Levine, who wrote the lyrics and called the song his most personal track on the album.
 "Sad" is a piano ballad that is similar to the music of British singer-songwriter Adele.
 It received generally mixed reviews from music critics; some of them called it a standout track on "Overexposed", however, others criticized Levine's voice on the song.
 Following the release of the album, due to strong digital downloads, the song peaked at number 12 on the singles chart in South Korea.
M.O.D. (abbreviation for Method of Destruction) is a crossover thrash band from New York City, fronted by Stormtroopers of Death vocalist Billy Milano.
 The band has been around for 31 years (minus one hiatus from 1997 to 2001), and released eight studio albums.
 With M.O.D., Milano sought to continue on the musical path of the bands Anthrax, Stormtroopers of Death and Nuclear Assault, mixing shades of hardcore punk with thrash metal and often humorous and politically incorrect lyrics.
"She Will Be Loved" is a song by the American pop rock band Maroon 5.
 The song was written by frontman Adam Levine and lead guitarist James Valentine.
 It was released as the third single from Maroon 5's debut album, "Songs About Jane" (2002).
 The single peaked at No. 5 in the United States, and by December 2012 had sold more than 2,722,000 digital downloads.
 It peaked at No. 4 in the United Kingdom.
 In Australia, it reached No. 1, a position it held for five non-consecutive weeks.
 The single is noted for its music video starring Kelly Preston in a mother-daughter love triangle with lead singer Adam Levine.
 The video is also in Sepia.
"Say It Again" is a pop song written by Natasha Bedingfield, Adam Levine, and Mike Elizondo for Bedingfield's second album, "N.B." (2007) and features Adam Levine for background vocals.
 It was released as the album's third and final single on 8 October 2007 in the United Kingdom.
 The song was released as a digital download only and failed to chart in the United Kingdom.
20 Years Of Dysfunction is a DVD/CD released in 2005 by crossover thrash band Stormtroopers Of Death.
 Mainly created by singer Billy Milano, the material for the 2-disc DVD/CD is mostly culled from fan-shot amateur footage.
 The relative scarceness of available material has resulted in some hilarious decisions by the production team; for instance, "Milk" is sung by Danny Lilker but the video footage inappropriately shows vocalist Milano singing.
 Also notable is that the DVD does not include any material from the second Stormtroopers Of Death studio album "Bigger Than The Devil".