Super Junior's 5th Album

Mr. Simple - 미스터 심플 is the award-winning fifth studio album of South Korean boy band Super Junior. It was released on 3 August 2011 by SM Entertainment and distributed by KMP Holdings. This is the group's second album that features ten of the original 13 members, the first being their previous album, Bonamana. On 19 September 2011, a repackaged edition, re-titled A-CHa was released. It features four new tracks including title track "A-CHa" and "Superman" which was previously released in version B only.

At the year end award shows of 2011, the album won the Disk Daesang Award at the 26th Golden Disk Awards and 21st Seoul Music Awards, as well as the Album of the Year at the 13th Mnet Asian Music Awards. The album, excluding the repackaged version, is listed as the second best-selling album of the year for 2011. By the end of March 2012, the album has sold a cumulative total of 502,830 copies,hence making it the highest-selling album of their career.

On March 31, 2011, leader Leeteuk announced during the interview, "At the earliest, we’ll be coming out with our fifth album this summer.Leeteuk and Eunhyuk confirmed on their radio show "Super Junior Kiss the Radio" on June 1, 2011 that they had begun recording their upcoming album that day. Heechul tweeted on June 2, 2011 saying that the group "may be going crazy with preparations for our fifth album, but when it’s finally released, you’re all going to go mad. American dancer Kenny Wormald posted on his official twitter on July 11, 2011 that he had started the choreography rehearsal for the group's upcoming new single. On the same day, Leeteuk and Eunhyuk revealed on their radio show "Super Junior Kiss the Radio" that songwriter Jinu (hitchhiker) had contributed something for the new album. Shim Jae Won, current choreographer and former member of the disbanded SM group Black Beat tweeted a picture showing cups with Super Junior's names written on them., providing possible formation for the song's choreography, as well as two pictures of the choreography practice of the group the next day showing only the lower half of their bodies. A teaser photo was released on July 20, 2011, with the first photo featuring Eunhyuk. Other photos followed, in order: Donghae, Leeteuk, Shindong, Kyuhyun, Sungmin, Ryeowook, Yesung, Siwon and Heechul. On the same day, it was announced that the album is set for an August 3 release. On July 22, 2011, the group began filming the music video for their new lead single. The filming for the music video wrapped up July 24, 2011, with Shim Jaewon consistently updating the group's filming activity. On July 25, Jeon Hoon of Sonic Korea Studio announced that he is mastering the new album. Two video teasers were released on August 1, 2011, in which the first teaser gained a million views on YouTube a day after its release, the second teaser passing a million views by the second day. The first teaser, by the end of the second day, had surpassed 2,500,000 views. The digital single was released on the 2nd as well as the whole digital album format through various Korean online music sites like Melon, Dosirak and Bugs, where it became an instant digital chart-topper in South Korea in just an hour of release. That day it was also made available worldwide on iTunes, where it charted at #28. The physical format of the album was released on August 3. The group will also have a press conference regarding the new album on August 4 at the Imperial Palace Hotel in Seoul, and the music video itself will be revealed the same day on the conference. The music video reaching more than half a million views within the first few hours of release, and comment numbers increasing by about 200 per minute. The music video passed 1.5 million views by the end of the first day, and 3 million by the end of the second, views and comments steadily growing all over the world. Currently, the music video has over 40 million views.

The group first held a press conference at the Imperial Palace Hotel in Seoul, which attracted about 200 reporters, including about 70 foreign journalists from Japan, China, Taiwan, Thailand, Hong Kong and Singapore and declared that this will be the group's current last studio release due to planned enlistment of group leader Leeteuk, as well as member Heechul in the army sometime in 2012. The group expressed that they will promote the album as long as possible since Leeteuk will be enlisting to the army and that they are in plans of a world tour. Leeteuk added that after his discharge from the army, they will go on to release an album afterwards. Super Junior had their debut performance of "Mr. Simple" and a non-album track called "Superman" at Music Bank on August 5, 2011, followed by Music Core on the 6th, Inkigayo on the 7th and M! Countdown on the 11th. However, promotions for the song will end on August 28 due to the enlistment of member Heechul to the army on September 1, 2011. On August 26, 2011, a music video for the album's supporting single, "Superman", was revealed via SM Entertainment's SMTOWN YouTube page, in which the music video shows various clips from theirSuper Show 3 tours as well as the photoshoots and music video making for "Mr. Simple".

The album was release in 11 countries across Asia. including Taiwan on September 6, 2011 by Avex Taiwan. The album was supposed to be pre-released in the Philippines byUniversal Records on October 1, 2011 but was moved to October 8, citing manufacturing problems caused by typhoon Nesat. The Type A album was officially released in the country on November 24.

After the released of "Mr Simple" in Japanese, the group followed-up with the release of "Opera" in Japanese. The single album also include the travel-themed mid-tempo ballad "Way", Japanese original music video and making-of DVD. It has been available for pre-order from 11 March 2012.