Captain Ben Stokes (31) confirmed the right-hander comes into the team in place of fellow Yorkshireman Bairstow, who was ruled out for the third test and the Twenty20 World Cup by a freak injury suffered on the golf course.

"I'm really looking forward to going out and watching him play this week, but he's deserved his opportunity," Stokes told a news conference at The Oval on Wednesday.

"I think I mentioned a few weeks ago he will be someone who represents England in all three formats for a long time,” he said of Brook, who made his international T20 debut on the tour of the West Indies in January and is a former England under-19 captain.

"It's exciting to see him get his opportunity this week with the whites on," Stokes added.

Brook is averaging 107.44 with the bat for Yorkshire in the County Championship this year and scored 140 runs for England Lions against South Africa in their warm-up match at Canterbury before last month’s first test.

"The way in which our middle order has been playing this summer, I feel as if Harry coming in, the way he goes about his game with the bat in his hand is pretty much a like-for-like replacement.

"He's always going to look to take the bowling on, take the positive option. It's obviously devastating to not have Jonny but I'm very excited we get a replacement with the skill Jonny possesses,” said Stokes.

The Oval test will decide the series which is tied at 1-1.

South Africa won the first by an innings and 12 runs at Lord’s only to be thrashed by an innings and 85 runs in the second test at Old Trafford.

"We put the Lord's defeat behind us and we concentrated on Manchester so I know that the South Africa team will be doing the same thing here,” the England captain added.

"I think it's great for the series that it goes down to the wire. I know that South Africa are going to come out firing but it's how we respond to the questions that they ask us."