The 17-year-old singer belted out Jessie J‘s “Mama Knows Best,” while the Florida duo sang their own rendition of Taylor Swift‘s “I Knew You Were Trouble.”
“blown away by dress rehearsal. every one sounds and looks AMMAAAZZZINNNGGGG!” Alex & Sierra tweeted earlier in the day.
Watch Ellona Santiago and Alex & Sierra perform below!
Ellona Santiago – “Mama Knows Best”
Alex & Sierra – “I Knew You Were Trouble”