album İki Deli, which was released in December 2015. To promote the album, Yener appeared on various television programs and went on a concert tour known as Sebastian 2015 Tour. Background and release After making electronic music for a period of time, Yener started to perform pop songs and released the album Hande'ye Neler Oluyor? in 2010. Sinan Akçıl wrote all of the songs on the album and continued to work with Yener on her subsequent studio albums, Teşekkürler (2011) and Kraliçe (2012). In March 2013, it was reported that Yener and Akçıl's "checkered" friendship had ended and they would not work on the same project again. After her friendship with Akçıl was over, Yener started to take new songs from Berksan. In May 2013, her new single "Ya Ya Ya Ya" was released, followed by "Biri Var" in November 2013, both of which were written by Berksan. "Ya Ya Ya Ya" ranked second on Turkey's official music chart and, after its release, Yener immediately began to work on her new album. In September 2013, it was reported that she had taken new songs from Altan Çetin, who had written songs for her early albums Senden İbaret (2000), Sen Yoluna... Ben Yoluma... (2002) and Aşk Kadın Ruhundan Anlamıyor (2004). On 28 December, Yener stated: "I'm making a whole new album for the new year. All the musicians who have had a big influence in my music career will be a part of this album with their most special songs. Be prepared for surprises. You will be very surprised with this album in the new year. We are working very intensively. The biggest surprise is to start working again with Altan Çetin after 10 years. Together we will bring out beautiful songs again. The album also has a song written by Berksan." On 31 December at her concert, she announced the album's title by saying: "I've started working on the album now, I wish everyone a perfect year because my album is called Mükemmel [Perfect]." In January 2014, it was confirmed that besides Altan Çetin and Berksan, Mert Ekren would also write a number of the songs in the album. In March, Yener shared the lyrics for the song "O Kadın Gitti" to mark the International Women's Day. In April, it was announced that Mehmet Erdem would be the featuring artist on the song "Unutanlar Gibi". On 15 April, the song