Recent music trivia question

[Hakuna Machado]

I didn't even have to look that up. I can't believe I knew something like that.

[ucffans]

Is it John Legend?

You got it!

I was surprised Alicia Keyes wasn't one of them, but she wasn't.

[Hakuna Machado]

The third one currently is the number 1 song this week! That should be a pretty good clue!

Is it John Legend?

[ucffans]

The third one currently is the number 1 song this week! That should be a pretty good clue!

[ranbethscards]

I checked with ask.com and it gave me only two names... Bruno Mars and Adele.

[ucffans]

IN the history of Top 40 countdowns, there have only been 3 songs to be #1 which used ONLY piano and vocals. All 3 have taken place in the past 5 years. Can you name the singers? (and their songs if you feel so inclined)