Question: Australian Idol's Anthony Callea's debut single is also commonly known as a duet between who?
Context: "Per Sempre (For Always)" is the fourth and final single by Anthony Callea from his self-titled debut album "Anthony Callea". Wesley Dean "Wes" Carr (born 14 September 1982), also recording as Buffalo Tales, is an Australian singer-songwriter and multi-instrumentalist, best known for winning the sixth season of "Australian Idol" in 2008.  He released his first studio album, "Simple Sum", independently in 2008 shortly before entering "Australian Idol".  After "Idol", he signed a record deal with Sony Music Australia and released his debut single, "You".  The song peaked at number one on the ARIA Singles Chart and was certified Gold by the Australian Recording Industry Association (ARIA).  Carr's second studio album, "The Way the World Looks", soon followed after.  It reached number two on the ARIA Albums Chart and also achieved Gold certification.  The second single "Feels Like Woah" peaked at number 14 and gained Gold certification.  In June 2011, Carr released "Been a Long Time", the lead single from his third album.  It peaked at number 33 on the ARIA Singles Chart.  In November 2011, Carr announced that he was no longer with Sony and would be releasing his album independently.  In August 2012 Carr released an EP titled "Blood & Bone" under the pseudonym Buffalo Tales.  His third studio album "Roadtrip Confessions" was released in June 2013 and debuted at number 83. "Hurts So Bad" is the third single released by "Australian Idol" series two runner-up Anthony Callea, and features on his self-titled debut album "Anthony Callea" (2005).  It was his third consecutive top ten single in Australia. "Here I Am" is the debut single by 2007 "Australian Idol" winner Natalie Gauci, written by Lindy Robbins and Tom Leonard.  The single was performed by the final two contestants – Gauci and Matt Corby – during the penultimate episode of "Australian Idol 2007". Anthony Cosmo Callea (born 13 December 1982) is an Australian singer-songwriter and stage actor of Italian descent (parents Santina and Cosmo) who rose to prominence after being the runner-up in the 2004 season of "Australian Idol".  Callea's debut single "The Prayer" is the fastest-selling single by an Australian artist, held the No.1 spot on the ARIA Singles Chart for five weeks, a record for the debut single of an "Australian Idol" contestant, and was the second-highest selling Australian single of the last decade. "Live for Love" is a pop rock ballad by Anthony Callea from his second album "A New Chapter" (2006), and the first single released from the album.  Anthony performed the song live at Highpoint Shopping Centre in Melbourne on 9 November, and also on "Australian Idol 2006" elimination night on 6 November.  When purchased at the iTunes Store, this single comes with an exclusive track entitled "Meant for Love", which didn't make the album's final cut. "Australian Idol" screened on Channel Ten for seven seasons between 2003 and 2009, and a number of contestants were signed to record labels, while others released their music independently.  Since 2003 "Australian Idol" acts have impacted significantly on the Australian music charts, with 33 number ones and 139 platinum and 39 gold certifications.  Eight Idol releases appeared in the 2000 - 2009 ARIA End of Decade Charts, and 24 releases have been nominated for Highest Selling ARIA Music Awards.  Idol contestants have also been nominated for 25 ARIA Awards in public vote categories, where the nominees are most commonly selected from the highest selling acts of the year.  There have also been 37 industry judged ARIA Award nominations.  To date there have been eight wins in sales and public vote categories, and in 2013 season one winner Guy Sebastian and season four runner up Jessica Mauboy became the first Idol contestants to win industry voted ARIA Awards. "Rain" is the second song released by "Australian Idol" series two runner-up Anthony Callea, and features on his self-titled debut album "Anthony Callea" (2005).  It was released as a double A-side set features the song plus his recording of Simon & Garfunkel's song "Bridge over Troubled Water", which he performed on "Australian Idol". "The Prayer" is a popular song written by David Foster, Carole Bayer Sager, Alberto Testa and Tony Renis.  It is most commonly known as a duet between Celine Dion and Andrea Bocelli.  It is from "Quest for Camelot: A New Chapter is the second album from Australian pop singer Anthony Callea.  It features the singles "Live for Love" and "Addicted to You", both of which Callea performed at popular morning show "Sunrise".  Callea co-wrote fourteen of the fifteen songs over a year.  The album runs a length of just over an hour, containing many more upbeat and rocky songs in comparison with his self-titled debut.
Answer: Celine Dion and Andrea Bocelli