Siya Kolisi says he cannot imagine what the scenes will be like in South Africa if the Springboks beat England on Saturday and are crowned world champions.

Kolisi, the Springboks' first black captain, will spearhead a bid for South Africa's third title after triumphs in 1995 and 2007.

And although the twice-world champions are underdogs in Yokohama, it is a dangerous game to write them off.

"I was obviously very young in 1995, so I don't remember anything about that, other than the videos and images I've seen," Kolisi said.

"It was definitely beautiful to see that, and I got to experience that in 2007 when I watched and saw what it did for the country.

"It does make a huge difference, and it's big back at home. I haven't seen this much support since I've played for the team.

"The president was speaking about it in parliament, asking the whole country to wear Springbok jerseys today and, if you are in a car, you must hoot at one o'clock.

"We know how much rugby means to the country and what it has done in the past.

"We have different races in our team and that is one of our strongest points, and that is something we want to show by the way we play – that we can achieve stuff together as long as we buy into whatever it is that we want to achieve.

"We have the country behind us, which is something huge. We are going to do our best tomorrow, and we really trust our plan.

"We've seen the videos, and I can't imagine what it would be like (in South Africa) were we to win the trophy tomorrow."

Kolisi will be watched by his father, who has made the journey to Japan for his first trip abroad.

"I am really happy that I could organise for him to come," Kolisi added. "It's his first time overseas, so it is something different for him.

"He came with my best friend, and it's one of the things I am grateful for about playing rugby – that we can do things like this for our family members."

Kolisi was appointed Springboks skipper in May 2016, and Saturday's final will be his 50th cap, but it has not all been plain-sailing.

"It was very tough at the beginning," he said. "When it (captaincy) got announced, it was a big thing back at home and around the world.

"It took its toll on me at the beginning, and my performance dipped quite a lot.

"We played England in a June series, and I wasn't playing at my best. I think it was just a bit too much, so I had to work hard on myself.

"It's not about me and what it would mean for me, but more about what it would mean for the team.

"We are different South Africans from different walks of life, but we bought into coach Rassie Erasmus' plans and we just said 'this is what we want to achieve'.

"We've given it everything, so it would be huge to show that, as a country, no matter where we come from, we can buy into one plan and we can achieve our goals."

England are bidding for a first world title since 2003, and it promises to be an intriguing encounter.

Kolisi added: "The past four games against England, it has been an arm-wrestle and swings of momentum. I am expecting that, and it's all about who can handle that the most.

"But you never know, there might be beautiful tries being scored. A lot of things have happened in this World Cup, so you can expect anything.

"Pressure can help you lift your performance. It is all about how you channel it.

"It is not another game – it is a World Cup final. Not many players get this opportunity, and we know that as a team. It's a special day."