Now That's What I Call Music! 78 or Now! 78 is a double-disc compilation album that will be released in the United Kingdom on 11 April 2011 on CD and downloadable formats. The album is the 78th edition of the UK Now! series. 　　Now 78 features six songs which reached number one on the UK Singles Chart: "Grenade", "We R Who We R", "When We Collide", "Price Tag", "What's My Name?", and "The Time (Dirty Bit)". 　　This album has double appearances from Jessie J, Ellie Goulding, Tinie Tempah, Taio Cruz, Chris Brown and Wiz Khalifa; in addition to a triple appearance from Rihanna.