While there are covers of popular songs by the millions on YouTube, very few rarely ever stand out. Here's one that's going viral all over the Web right now - because it's simply too good! Two sisters (Lennon,12, and Maisy Stella,8) do a simple, yet impressive, rendition of Swedish popstar Robyn's hit song 'Call Your Girlfriend.'

Not only do the two girls have sweet voices, they harmonize beautifully. There's no cowbell, but they use margarine tubs instead! Check out Lennon & Maisy's cover of 'Call Your Girlfriend' below.

The "beats" blend in perfectly, and this cover is easily one of the more unique renditions of a pop song by little kids we have seen to date. Lennon and Maisy have done other covers which can be found on their YouTube channel. With their rising fame, will we see these two on 'Ellen' soon? (Sophia Grace and Rosie can't hog all the spotlight.)