"Iridescent" is a song by American rock band Linkin Park. It was announced as the band's third US, fourth international and overall final single from their fourth studio album, A Thousand Suns, which was released on September 14, 2010. A music video for the song was directed by Joe Hahn, the band's turntablist. "Iridescent" serves as the theme song for the film Transformers: Dark of the Moon, continuing the streak of the band's songs serving as the theme songs of the Transformers films. The song received positive reviews and became a moderate success.

In April 2011, a splash screen appeared on the band's website, that contained a distorted Autobot image and a snippet from "Iridescent" (this is no longer available). A few days later, Mike Shinoda, one of the band's lead vocalists, confirmed that the song will be the fourth single from A Thousand Suns. He also confirmed that a shorter version was made for the film Transformers: Dark of the Moon, which is circulating around the internet. Shinoda said that the collaboration began when Michael Bay, the director of the film series, phoned him about the possibility of the band continuing their run with songs paired with the Transformers films (having chosen "What I've Done" for the first film and having recorded "New Divide" specifically for the second). Shinoda decided to put "Iridescent" in the film due to the fact it was a fan favorite and called it a "natural fit", despite the song not being an "in-your-face" kind of tune.

The film's composer, Steve Jablonsky, who is a longtime fan of the band, agreed with the choice, saying that the song fit well with his score, as well as the film's story. Both Shinoda and Jablonsky agree that the song is an appropriate choice for the film, since the film is described to be more "positive" than the previous films and is consistent with where the band is at (learning from mistakes; going in different directions).

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