This is a randomised, placebo controlled, four way crossover thorough QT study to evaluate the effect of repeat dose fluticasone furoate/GW642444M combination on the QTc interval in healthy male and female subjects. Up to 85 subjects will receive inhaled placebo and inhaled fluticasone furoate/GW642444M combination (200/25 microgram (mcg) or 800/100 mcg) and oral moxifloxacin (400 milligram (mg)). The inhaled treatments will be given double-blind once daily in the morning for 7 days with a single-blind placebo tablet also administered on Day 7. Moxifloxacin (positive control) will be given as a single-blind single dose on Day 7 in the morning with inhaled double-blind placebo administered in the morning on Days 1-7. Individual time-matched changes from baseline in QT duration corrected for heart rate by Fredericia's formula (QTcF) (difference from placebo) for fluticasone furoate/GW642444M 200/25mcg will be determined 0-24 hours (h) after dosing on Day 7 (primary endpoint). Secondary endpoints will include changes from baseline in QTcF, QT individual correction factor (QTci), QT duration corrected for heart rate by Bazett's formula (QTcB), and QT interval at each timepoint after 7 days dosing of fluticasone furoate/GW642444M 800/100mcg and single dose oral moxifloxacin (400mg) and changes from baseline in QTci, QTcB, and QT interval at each timepoint after 7 days dosing of fluticasone furoate/GW642444M 200/25mcg. Plasma concentrations (0-24h) and pharmacokinetic parameters of GW642444 and fluticasone furoate will also be derived.