England and France have largely breezed their way through the Women's Six Nations, but that will change at Twickenham on Saturday.
A tight scoreline is expected as both sides fight for a Grand Slam in a fervent atmosphere stoked up by an expected crowd of more than 50,000.
England have been given a boost with both captain Marlie Packer and prop Hannah Botterman coming through injury scares to start.
There are four players brought into France's XV after last weekend's victory against Wales.
Scrum-half Pauline Bourdon, prop Rose Bernadou, lock Manae Feleu and flanker Axelle Berthoumieu all start, with Charlotte Escudero moving to number eight.
Victory may come down to individual brilliance. Here are three of the key match-ups to look out for.
Helena Rowland v Gabrielle Vernier
Inside centre Gabrielle Vernier has been one of France's top performers this tournament, becoming a key cog in an increasingly exciting attacking structure.
Conversely, England's Helena Rowland is making her first start of the year at outside centre - an unfamiliar position.
Rowland was a reliable and smart full-back for England at the World Cup last year but missed out on the final defeat because of a foot and ankle injury sustained in the semi-final.
The 23-year-old will also take on goal-kicking duties on Saturday - an area in which England have struggled this tournament.
Despite that lack of game-time, England head coach Simon Middleton says Rowland is "definitely the right call", adding that she had played 13 "an awful lot in training".
"Sometimes you roll the dice a bit and see what comes up," Middleton said.
"I think Helena is such an adaptable player, such a talented player. She just gives us a different dimension."
Holly Aitchison v Jessy Tremouliere
Fly-half Holly Aitchison facing Jessy Tremouliere is a case of the student against the master.
Tremouliere, 30, is a legend of the game and former World Rugby player of the year winner. She will retire from international rugby after Saturday's match.
Aitchison, 25, took the reins at 10 at the start of the Six Nations because England's usual starting fly-half, Zoe Harrison, is missing the tournament with a torn anterior cruciate ligament.
Aitchison has blossomed, taking charge of England's improving attack and distributing the ball to her talented back three.
Tremouliere may have more experience of big occasions to prepare her for the Twickenham crowd, but both have played sevens at the Olympics and neither is afraid of a creative cross-field kick.
England captain Packer says of the France 10-12 combination of Tremouliere and Vernier: "We need to make sure we shut that down early."
Marlie Packer v Gaelle Hermet
Gaelle Hermet may no longer be France's captain, with Audrey Forlani taking that role for the tournament, but she is still a leader for Les Bleues, as Packer is for England.
Packer herself described Hermet's performance against Wales as "massive".
The England captain's return to fitness after sustaining an ankle injury in last weekend's match against Ireland is a massive boost for the Red Roses.
The flankers will face off at the breakdown, which will likely be a key battleground as both sides attempt to stop the other from getting quick ball to fuel their rapid backlines.
Packer has won five turnovers in the tournament so far and Hermet four. The England captain is the tournament's top try-scorer with six.
As well as being motivational presences in the pack, both players are equally capable of a break down the wing more characteristic of a back-three player.