England can win the Rugby World Cup - but only if the country gets behind the team.
That, said All Black great Jonah Lomu, would create a "formidable" force within the tournament.
After showing the Brits how the haka is done, Lomu told the Evening Standard that England "could win it".
New Zealand come in as favourites but that doesn't mean anything, the famous winger said.
"No one's done it back-to-back so the All Blacks will be trying to do that but there's about six teams on the day that could beat each other," he said.
"If [England] get the support behind them and they build momentum they're going to be formidable and hard to beat, especially here at home. Everyone knows that. If you come to England and you're playing England at rugby HQ it's going to be tough but you've got to play at your best to beat them because it's like playing the crowd as well as the team, it's not just them.
"Hopefully people will get behind them and if they do it's going to be a tough day at the office whoever they play."
Lomu has been in Britain for three weeks with his wife and children and yesterday stopped by London's Covent Garden to show the locals how the mighty haka is done.
He performed that traditional Ka Mate haka with volunteers from Ngati Ranana London Maori Club as part of MasterCard's Rugby World Cup 2015 campaign.
While Lomu's calls of "Ka Mate" rang out in London, All Blacks captain Richie McCaw was having a less fearsome time at training.
McCaw took an uncomfortable-looking fall, ploughing head-first into the turf. But All Blacks fans will be pleased to hear he came away unscathed.
The team face their first challenge of the World Cup on Monday morning when they play Argentina.