Katy Perry's new single 'Roar' was officially released yesterday (12th August), despite being leaked two days early.

Katy Perry
Katy Perry at the 2013 Delete Blood Cancer Gala at Cipriani Wall Street in New York.

'Roar' has already done incredibly well, heading straight for number one in many singles charts. Yesterday (Monday 12th), Perry tweeted thanking fans for buying the single. She wrote "HEY! THANKS WE'RE #1 IN 20 COUNTRIES ALREADY," adding "How many countries are there actually?"

The answer is, Katy Perry, 196. Although this figure consists of the countries recognised by the UN, it is widely debated. 

Anyway, 'Roar' was leaked two days before its release date but this did not deter Perry who tweeted "looks like there's a tiger on the loose" in response to the prematurely released single. 

'Roar' seems likely to become another of Perry's anthems, joining the ranks of 'Firework' and 'Wide Awake'. It is, however, slightly different to her usual upbeat songs with a heavier drum beat. Perry seems to have indicated she is changing her image with the release of her new album. In promotional material for 'Roar', Perry sets fire to her trademark blue wig. 

Watch Katy Perry's 'Roar' lyric video:

Perry continues to create hype around her upcoming fourth studio album, Prism. As part of the album's promotion, a gold truck has been touring the United States. Fans have been encouraged to tweet in a picture if they see the gold truck, which is emblazoned with the album's release date. 

The truck is currently enjoying some TLC after being involved in an accident in Pennsylvania, but Perry promises it will be back on the road shortly.

Prism is due to be released on October 22nd 2013. 

Katy Perry
Katy Perry at the 2013 ASCAP 'I Create Music' Expo held at the Loews Hollywood Hotel in L.A.

Katy Perry
Katy Perry at the 2013 White House Correspondents Dinner held at the Washington Hilton.