Live Results 8: Who's In The Semis?

Dermot O'Leary reveals the results of the latest public vote. The two acts with the fewest votes must take part in a sing-off, and then judges Simon Cowell, Dannii Minogue, Louis Walsh and Cheryl Cole decide who stays to compete in the quarter-finals, and who must leave for good. Also featuring live performances from Rihanna and Alicia Keys.