England's Kevin Pietersen insists he is fit ahead of Ashes opener

England batsman Kevin Pietersen has insisted that his knee is "absolutely fine" following concerns over his fitness.

The 33-year-old was recently declared fit for the opening Ashes Test against Australia in Brisbane, despite a persistent knee injury.

Pietersen reiterated that he was fine once again today when he was asked by a Twitter follower if his knee was 'holding up'.

The first Test in Brisbane beginning on Thursday this week will mark the batsman's 100th match.