Frederik (real name Ilkka Juhani Sysimetsä, born 2 February 1945) is a Finnish singer.
 He is known by his nickname Reetu.
 During his lengthy career of machostyle disco and pop music, he has been awarded with five gold and three diamond records.
 One of his contemporary nicknames is "Junttidiscon kuningas" ("King of redneckdisco").
 Frederik started his musical career as an electric organist in a pop group named Jim & The Beatmakers.
 He played later in a beat pop group named The Roosters in the mid-1960s.
Saiko is a Chilean Synth-pop and Pop rock band established in the late 1990s.
 Throughout their career they have achieved great notoriety in the musical Chilean scene, largely to the charisma, image and voice of their vocalist, Denisse Malebrán, and the musical talent and experience of Rodrigo "Coti" Aboitiz and Luciano Rojas, both Former members and founders of the Chilean group La Ley.
 To date they have released seven studio albums: Informe Saiko (1999), Campos finitos (2001), Todo Saiko (2003), Las horas (2004), Volar (2007), Trapecio (2013) and Lengua Muerta (2017).
Popstars is a UK talent show series that was broadcast on ITV in early 2001.
 It was the first UK series of the international "Popstars" franchise, and was billed as a documentary on the formation of a modern pop group.
 The series began with audition rounds of aspiring singers (good and bad) performing songs before a panel of judges.
 The best performers were selected to come to London for further rounds of auditions.
 Over the weeks, the judges eliminated various singers from the auditions until just a few singers were left in contention.
 In the final weeks, five contestants were chosen by the judges to form the new pop group Hear’Say.
 The programme then showed the group recording and promoting their first single, documenting their first ventures into the music industry.
My Life Story are a British indie pop group who peaked in the mid to late 1990s, when they were regarded as part of the Britpop movement.
 Fronted by singer/songwriter Jake Shillingford, the group was formed in London around 1991, and inherited their name from an earlier group in which Shillingford had appeared.
 A cross between a pop group and a chamber orchestra, the band's sound was heavily oriented toward orchestral instruments.
"Te Quise Tanto" (English: I Loved You So Much ) is a song written by Coti Sorokin, Andahí and A. Schinoff and produced by Emilio Estefan Jr. and recorded by Mexican pop singer Paulina Rubio, and was included on her studio album "Pau-Latina" (2004).
Magneto was a popular Mexican boy band of the 1980s and 1990s.
 The band formed on February 14, 1983.
 In 1986, Magneto was featured in "Siempre en Domingo," a Mexican entertainment show viewed across Latin America and parts of Europe.
 Mexican teen pop group Magneto emerged in 1983.
 Their first record, Dejalo Que Gire came in 1984, followed by Super 6 Magneto.
 The Latin pop outfit suffered several lineup changes before achieving their first gold record in 1986.
 Mostly playing dance-pop songs, the five-member ensemble started touring Central America after climbing charts with "Todo Esta Muy Bien," and "Soy Un Soñador."
 However, their breakthrough came after issuing a Spanish-language version of Desireless' "Voyage Voyage," a French pop hit from the '80s.
 In 1992 the boy band played the lead in their own movie, "Cambiando el Destino".
 Magneto won the Lo Nuestro Award for Pop New Artist of the Year, and received two nominations for the Lo Nuestro Awards of 1993: Pop Album ("Magneto") and Pop Group of the Year.
 Nevertheless, the original Magneto disbanded in 1996 after a sold-out show at Mexico City's Auditorio Nacional.
Thomas Forbes "Tommy" Hoehn, Jr. (November 2, 1954June 24, 2010) was an American singer, songwriter, keyboard player, and guitarist.
 Along with Jon Tiven, he led the Memphis power pop group Prix before embarking on a solo career.
 He also provided backing vocals on Big Star's third album, "Third/Sister Lovers", and collaborated with Big Star members Alex Chilton and Chris Bell as well as Memphis power pop group The Scruffs.
Roberto Fidel Ernesto Sorokin Esparza, who performs under the stage name Coti, is an Argentine singer-songwriter, best known for collaborations with other Spanish-language artists like Andrés Calamaro (Arg), Julieta Venegas (Mex), Paulina Rubio (Mex) and Luis Miguel in his last album.
 His 2005 release, "Esta Mañana y Otros Cuentos" went gold in both Argentina and Mexico, while going double platinum in Spain.
Johnny Shentall (born John George Shentall; 3 September 1978) is a British pop singer.
 He was first a member of the pop group Boom!
 before joining another pop group, Hear'Say in 2002.
Paulina Susana Rubio-Dosamantes (] ; born 17 June 1971) is a Mexican singer, actress, television music competition judge, hostess, model and businesswoman.
 She began her music career as original member of the pop group Timbiriche from 1982 through 1991, before leaving the group in order to focus on her solo career.

Question: Coti has collaborated with the singer who began her career with what pop group?
Answer: Timbiriche