Leyton Orient centre-back Ben Chorley admits he has been surprised by Norwich City's form this season.

Chorley, who faced the Canaries twice last season in League One, is expected to have a major role in the heart of the visiting defence this afternoon.

'Norwich are flying high and have surprised me so much by being joint second in the Championship,' he said.

'I know a few of them and they've also bought four or five League One players.

'It will be a great atmosphere with 25,000 people and they always make a good noise.'

Chorley is expected to line up alongside the returning Terrell Forbes, who is back after suspension, at Carrow Road, when the Os hope to end a run of eight games where they have failed to keep a clean sheet.

'I like playing with him, I think it works well,' said Chorley. 'But whichever way the manager goes I think I will be ready for it.

'We need to improve. Five or six weeks ago we were getting clean sheets every other game and we need to get back to that. It's what we're paid to do.'

The last time the teams met was in east London in April when City were beaten 2-1.

'We can go and enjoy the occasion and it will bring a little bit more money into the club,' said manager Russell Slade.

'We won't lie down. It's a great occasion the FA Cup, so who knows?

'I'm looking forward to it. The FA Cup is always good as it gets us away from pressure of the league, but it's a challenge against a team in form like Norwich who are really flying.

'I want the players to enjoy the experience of playing at Carrow Road and enjoy playing a team who could be in the Premier League next season.

'We'll need resilience, a real focus, we'll need to keep the ball and be comfortable on it and we have to be a threat.

'Any kind of result, even if we bring them back to Orient, would be a great result and our chairman would be over the moon. We know it will be tough but we'll be up for it.'

His leading scorer, scorer Alex Revell, says the pressure is all on City.

'The pressure won't be on us for a change,' he said.

'If we go there and perform, it could be a nice little win for us to keep the momentum going,' he said.

'It's another away game and it'd be nice to have them here. A few people were like 'Hmmm, it's not a very good draw' – I think it's a very good draw and it's a chance for us to go there and show what we can do,' he said

Slade has made his first permanent signing of the January transfer window after Andrew Whing agreed a deal to stay until the end of the season.

The 26-year-old defender has been on loan from Brighton, playing five games, but his deal with the Seagulls has been cancelled by mutual consent.

Slade said: 'He's done well during his loan period and has added greater depth to our defence, particularly given his versatility.

'I'm still looking to strengthen the defensive unit, and I'm sure there's still some wheeling and dealing to be done in the transfer window yet.'