RnB superstar Bruno Mars gets away with a Grammy 2012 nomination - for a single released in 2010.

One might ask, "how come?"

The crooner isn't the only one who's getting some Grammy love. Katy Perry's 'Firework' and Mumford & Sons' 'The Cave', who are up against 'Grenade' for Record of the Year, were also both released in 2010.

Not to worry though, there isn't any conspiracy here.

Grammy's official rules, which is available to the public, is clear enough to express its allowance for late 2010 releases.

"For the 54th Annual GRAMMY Awards, albums must be released between Oct. 1, 2010 and Sept. 30, 2011. Recordings must be in general distribution in the United States, i.e. sales by label to a branch or recognized independent distributor, via the Internet, or mail order/retail sales for a nationally marketed product."

Perry's 'Firework' came out on October 26, 2010, while 'The Cave', as far as its US release is concerned, also come out on the same day. Mars' 'Grenade', on the other hand, was released a month earlier - September 28, 2010.

However, before any protests commence, award official considered the release date of the album which it was included in, 'Doo-Wops & Hooligans', which was confirmed by E! to be on October 4, 2010.

All in all, the singer-songwriter's nominations on the 54th Grammy Awards total to 6: Album of the Year and Best Pop Vocal Album for 'Doo-Wops & Hooligans', Record of the Year, Song of the Year and Best Pop Solo Performance for 'Grenade', and Producer of the Year, Non-Classical.

The Filipino-American couldn't hide the shock of being shortlisted for the categories mentioned after he and his team, The Smeezingtons, performed at the Grammy Nominations Concert.

"Worked extremely hard on 'Grenade'. That was the hardest song on the whole album to finish because we knew we had something, and to get all that emotion out," Mars describes of his nominated single 'Grenade'.

"I think I can speak for all of us when I say that we're really happy that that song is being recognized because that's like our trophy song."