Most of the 2005 was spent working on a new album. As a solo act, Kazutoshi Sakurai appeared at Golden Circle vol.7 on February 28, 2005. Finally on June 29, 2005 the group released their 27th single . The single became a monster hit selling 569,000 copies its first week, and ending with 925,632 copies sold. As a quad a-side single, all four songs had a commercial tie in. promoted 'Pocari Sweat', "and I love you" promoted 'Nissin Cup Noodle – NO Border', became the theme song for the Japanese movie 'Fly Daddy Fly', and was used as a promotional song for Fuji TV's educational program 'Kodomo bangumi Ponkikkiizu, Gachagachapon'. Even though it was released as a single, it was classified as an album by the Recording Industry Association of Japan. A month later the group attended Kazutoshi Sakurai's 3-day festival 'ap bank fes’ 05' from July 16, 2005 through July 18, 2005, followed by 'SETSTOCK '05' at Kokuei bihoku kyuuryou park on July 23, 2005 and 'Higher Ground 2005' at Umi no nakamichi kaihinkouen outdoor theater on July 30, 2005. Three months later on September 21, 2005, I Love U (I♥U), Mr.Children’s 12th original album, was released. Two months later Dome Tour 2005 'I Love U' began, running from November 12, 2005 through December 27, 2005 and were only the fourth artist in Japanese history to play at the Osaka, Tokyo, Sapporo, Nagoya and Fukuoka dome's. The tour ended in Tokyo Come where they played to 45,000 fans, bringing the tour total to almost 390,000 fans. By the end of the year the group managed to pass the 45 million mark in sold records.
Most of the 2005 was spent working on a new album. As a solo act, Kazutoshi Sakurai appeared at Golden Circle vol.7 on February 28, 2005. Finally on June 29, 2005 the group released their 27th single . The single became a monster hit selling 569,000 copies its first week, and ending with 925,632 copies sold. As a quad a-side single, all fo.ur songs had a commercial tie in. promoted 'Pocari Sweat', "and I love you" promoted 'Nissin Cup Noodle – NO Border', became the theme song for the Japanese movie 'Fly Daddy Fly', and was used as a promotional song for Fuji TV's educational program 'Kodomo bangumi Ponkikkiizu, Gachagachapon'. Even though it was released as a single, it was classified as an album by the Recording Industry Association of Japan. A month later the group attended Kazutoshi Sakurai's 3-day festival 'ap bank fes’ 05' from July 16, 2005 through July 18, 2005, followed by 'SETSTOCK '05' at Kokuei bihoku kyuuryou park on July 23, 2005 and 'Higher Ground 2005' at Umi no nakamichi kaihinkouen outdoor theater on July 30, 2005. Three months later on September 21, 2005, I Love U (I♥U), MrChildren’s 12th original album, was released. Two months later Dome Tour 2005 'I Love U' began, running from November 12, 2005 through December 27, 2005 and were only the fourth artist in Japanese history to play at the Osaka, Tokyo, Sapporo, Nagoya and Fukuoka dome's. The tour ended in Tokyo Come where they played to 45,000 fans, bringing the tour total to almost 390,000 fans. By the end of the year the group managed to pass the 45 million mark in sold records.