Hello is the debut extended play by South Korean girl group Mamamoo. It was released by WA Entertainment on June 18, 2014 and distributed by CJ E&M Music. It contains seven songs, including the single "Mr. Ambiguous", which was used to promote the album. The album was preceded by three additional singles—collaborations with Bumkey, K.Will and Wheesung, and Geeks. The album is a mix of musical styles, including R&B, hip hop, and funk.

Mamamoo's first single "Don't Be Happy", a collaboration with Bumkey, was released on January 9, 2014. Although it was not promoted, it charted at number 20 on the Gaon Digital Chart and number 24 on the Billboard Korea K-Pop Hot 100. They then released the single "Peppermint Chocolate" with K.Will (featuring Wheesung) on February 11. The song was a commercial success, charting at numbers ten and seven on the aforementioned charts. Mamamoo's third collaboration single, "Heeheehaheho", with duo Geeks, was released on May 30 and peaked at numbers 50 and 45.

On June 18, 2014, the group's first EP, Hello, was released. It contains the three previously released collaborations and four new songs, including the single "Mr. Ambiguous", which was used to promote the album. It was released in both CD and digital formats, but "Peppermint Chocolate" is only included on the CD version of the album. The album debuted at number 19 on the Gaon Album Chart in the third week of June 2014. "Mr. Ambiguous" entered the Gaon Digital Chart at number 53, and peaked at number 19 two weeks later. It also charted at number 28 on the K-Pop Hot 100. Mamamoo was surprised that the song became a hit, because it was tailored to their unique style and they did not think it had mass appeal. In November 2015, the album re-entered the Gaon Album Chart, peaking at number 16. This was due to the group gaining public attention after winning an episode of Immortal Songs: Singing the Legend.

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