Groups | Various Hometowns Share Tweet Latest Videos Alex & Sierra's "Great Big" Performance! Alex & Sierra left a mark with their performance of A Great Big World's "Say Something." What did their mentor, Simon Cowell, have to "say" afterwards? Alex & Sierra's "Great Big" Performance! Say Alex & Sierra's "Name" Alex & Sierra Get Into "Trouble" Alex & Sierra Sing The "Best Song Ever" Alex & Sierra Share The "Love" Meet The Final 12: Alex & Sierra Alex & Sierra Cover Robin Thicke The Top 16 Super Powers The Top 16 Hidden Talents The Top 16 Celebrity Crushes The Top 4 Groups In 15 Seconds or Less! The Top 10 Groups Sound Off About Simon! Alex & Sierra Knows Grease Is The Word Alex & Sierra: Yes, We Made It! Meet Alex & Sierra Latest Photos After a recap of Wednesday night's show, Mario Lopez congratulated the acts who had songs on the top of the iTunes charts today! But the big question was, did it translate into votes? Our youngest contestants often have a hard time when they find out they are eliminated, but Rion Paige handled the news with the same positivity she has used to face obstacles all her life. A huge congratulations to Restless Road, Alex & Sierra, Jeff Gutt, and Carlito Olivero for making it to the semi-finals. Ellona and Rion, we'll be seeing you soon! All four judges gave Alex & Sierra a standing ovation for their performance. Demi summed it up saying, "The two of you playing instruments is so magical and shows how talented you were. Whether you meant it or not, you never took your eyes off each other. It was so powerful. I really need you guys in the final four." Demi has been awfully nice when talking about her rival's teams tonight! Alex & Sierra had a lot to "Say" tonight. They went from "Say My Name" to "Say Something," a beautiful song by A Great Big World. On a smoke-filled stage with candles, the couple seemed totally in their element with this "Unplugged" theme. We got to see Sierra on the piano for the first time, and Alex was back on his guitar. Early on in the performance, the audience cheered loudly, and Simon had such a confident look on his face! Sierra's fingers were trembling, but her voice sure didn't waver. Alex & Sierra took on a song by one of our diva judges, Kelly Rowland (well, Destiny's Child). Singing "Say My Name," the couple ditched their boho, folksy looks for leather pants (Sierra) and a leather jacket (Alex). They gave the song the Alex & Sierra treatment, but still honored the original hit. Demi didn't think Alex & Sierra seemed nervous singing in front of Kelly, and she observed, "Sierra you've come out of your shell. I love you guys so much. It was really brave of Simon; it worked." Wow! Demi complimented Simon after each of his acts' performances. And did anyone create a gif of that side-eyed look Simon gave Paulina? Alex & Sierra The Top 6 dress rehearsal. Alex & Sierra Alex & Sierra look good all dressed up!