Rihanna is the kind of girl you don't easily approach to make a request of any sort. She's RiRi. But even when you're the biggest rock 'n' roll band in the world, like Coldplay, you still get a little weak in the knees and shy when asking RiRi for a favor. It's like you're the video game nerd who's about to ask out the captain of the cheerleading squad.

Coldplay's Chris Martin revealed to Ryan Seacrest on the latter's radio show that it took him a "about a year" to not be "too Hugh Grant'ish" and muster up the courage to request RiRi's vocal presence on the song 'Princess of China' on 'Mylo Xyloto.'

Given that Coldplay had never invited guests on their previous albums, this was new territory for them, but they were sure they wanted RiRi for the song. Drummer Will Champion was initially slated to deliver the parts that were eventually re-assigned to RiRi, but the band knew those verses needed a female touch and who better to provide it than Rihanna!

Martin recalled how he managed to "bag" Rihanna for the song. "We were at a New Years concert in Las Vegas with Jay-Z and she was there. We just got done playing so I had that tiny bit of confidence you get after a concert, and I managed to stammer it out, 'Would you maybe … Perhaps … Consider singing…' It was very 7th grade-y, but she was very kind, and sang on it."

How could she turn a stammering British bloke down, right? Um, yeah. Meanwhile, we're still stuck on that part about hanging with the Hova in Sin City! What fun that must have been.

Martin did deem RiRi's vocals on 'Princess of China' as "the best bit of singing on any of our albums ever!" We love those self-deprecating Brits.

Listen to the Coldplay Interview on 'Ryan Seacrest'