The London Wasps lock, who spurred England fight back last week against Australia, is rewarded with a start in the engine room aged only 21 replacing his Wasps’ teammate Tom Palmer who drops out of the squad as Saracens Mouritz Botha cover the second row on the bench.
Launchbury inclusion is one of six changes made by head-coach Stuart Lancaster ahead of the game.
Northampton back row Tom Wood, who returned from a long foot injury in recent weeks, comes in for Exeter‘s Tom Johnson at blindside while Gloucester‘s Ben Morgan replace Leicester’s Thomas Waldrom at No.8 following his hat-trick cameo against London Welsh in the LV Cup last Saturday.
In the front row, London Irish prop Alex Corbisiero comes straight into the starting XV for the injured Joe Maler despite making his competitive return only two weeks ago from the shoulder injury which kept him out of the South Africa tour last June.
There are two changes in the back line with Ben Youngs getting the nod at scrum-half over Danny Care who drops to the bench.
Out wide, Harlequins full-back Mike Brown will start on the left wing replacing Charlie Sharples.
Along Botha’s inclusion on the bench, London Irish centre Jonathan Joseph has recovered from an ankle injury which kept him out of the first two Tests and covers the midfield and the wings while James Haskell will provide some bulk as back row cover.
Lancaster said: “We have picked a team that will give us the best chance of beating South Africa. There were some tight calls, which is what you want as coaches, but the players we have brought into start have been training well, will bring a real motivation to make the most of their opportunity and will suit the challenge we face against a tough and physical South African team.”
There were injury worries with winger JP Pietersen and prop Gurthro Steenkamp for South Africa but both have been passed fit to face England.
Lock Eben Etzebeth’s inclusion to the team was also in doubt after the youngster was cited after the Scotland’s game but he was cleared of eye-gouging and retains his place in the team.
However, Heineke Meyer has made two changes to the bench with Pat Cilliers and Elton Jantjies coming in for CJ Van der Linde and Morne Steyn.
Heineke Meyer said: “It’s great to be able to field an unchanged team. We’ve been able to show some consistency in selection on this tour and that is a good thing. The players have worked extremely hard on the training field and it wasn’t easy to select the match 23 for each of the three Tests, but I’m happy that we managed to stick to combinations.
“The plan was always to give Elton a run on the tour. He’s shown earlier in the season that he can play Test rugby. It’s also good for his development as a player to experience the conditions here and to play in front of a big crowd like Twickenham.”
England: Goode; Ashton, Tuilagi, Barritt, Brown; Flood, B. Youngs; Corbisiero, T. Youngs, Cole; Launchbury, Parling; Wood, Robshaw (capt.), Morgan.
Replacements: Paice, Wilson, Vunipola, Botha, Haskell, Care, Farrell, Joseph.
South Africa: Zane Kirchner; JP Pietersen, Juan de Jongh, Jean de Villiers (capt.), Francois Hougaard; Pat Lambie, Ruan Pienaar; Gurthro Steenkamp, Adriaan Strauss, Jannie du Plessis; Eben Etzebeth, Juandre Kruger; Francois Louw, Willem Alberts, Duane Vermeulen.
Replacements: Schalk Brits, Heinke van der Merwe, Pat Cilliers, Flip van der Merwe, Marcell Coetzee, Elton Jantjies, Jaco Taute, Lwazi Mvovo.