Stop Living The Lie is his first stab at chart success - and a radically different departure from the debuts of golden guys Will Young and GarethGates.
Underwood himself took to the ice with his leg in cast for the finale, along with other contestants from the series - including Tim Vincent, Sarah Greene and GarethGates.
The show gave ITV1 its biggest ratings hit on a Saturday since GarethGates and Will Young fought it out to be crowned Pop Idol in February, with a 36% of the watching public.