this is from the sophia grace brownly youtube channel. >> i'm sophia grace, it's good to see you grace rosie show. today we're at the museum. >> this is 8-year-old sophia grace with her 5-year-old cousin, rosie. youtube sensation for a while. this is their latest video and people are going nuts over it. right here she's singing michael jackson's "thriller." ♪ this is thriller >> this is thrilla ♪ >> she's launching into katie perry's songs, "fireworks." ♪ baby, fireworks >> hold on, steven, this is for you, she's pulling a bieber. >> she's rapping and that's pulling a bieber. >> i know how much you love bieber's rapping. >> i got to have rosie. >> is it me or that could that kid sing a little bit? >> she's an awesome singer. they were on the ellen show. she sang a nikki minaj song. >> she's like the penn and teller of kids. >> does the little girl sing? >> is it weird that it's like russell brand in a little tutu with a crown on? >> it's a grammy, grammy, not granny. >> i don't think we've seen the last of these two. >> these little girls are so cute. i just want to fold them up and pu