Will Fireworks happen when Katy Perry and Rihanna finally lay down a track together? The two young pop singers have been in the works for years on collaboration, according to both. Yesterday Perry tells Radio 1 Live Lounge host Fearne Cotton more details about the inevitable duet.

We've collaborated on a lot of things, but just not songs yet. It's one of those things that's got so much build-up that we have to deliver, Perry said.

I want it to be like that Eurythmics and Aretha Franklin song 'Sisters Are Doin' It for Themselves'. But I definitely want to do something that is so iconic. [Rihanna's] kind of busy too. We're both busy but we planted the seed two years ago.

The 27 year old made waves yesterday after releasing a cover of the controversial Kanye West and Jay-Z track Ni-as in Paris, also on the Radio 1 Live Lounge, to much critical disdain. Though that off-the-cuff cover may have been rushed, Perry says she and RiRi are in no hurry to make their duet happen.

How disappointed would you be if that song came out and it's no good? Sometimes you have to wait for greatness, Perry said.

Rihanna confirmed to Access Hollywood last week that the two BFFs have had a collaboration in the works for years.

The song will probably come out in a while, RiRi said. I can't say it's happening right now, but it's going to happen. We are still trying to make a song together, Katy Perry and I. She is one of my favourite musicians as well as one of my favorite people in the industry.

This makes sense considering her justification for continuing to work with Chris Brown. The We Found Love singer told Ryan Seacrest for the sheer popularity of the match:

I reached out to him about doing 'Birthday Cake' because that's the only person that really made sense to do the record, she said. I thought about rappers, and I've done that so many times, and the hottest R&B artist out right now is Chris Brown. So I wanted him on the track.

As for the upcoming Katy Perry match, it only made sense:

She's very uncalculated, Rihanna said. Very sure of herself, and that's something that's very rare in this industry to find. We connected really quickly.