Wales beat France 14-13 to claim second place in the Six Nations
Earlier Ireland beat England 24-15 to secure their third Grand Slam
And Scotland won a thriller against Italy 29-27 in Rome
Highlights & reports of all three matches on the BBC Sport website
Wales v France (17:00 GMT)
The final game of the day sees Wales host France in Cardiff.
Wales need a bonus-point victory over France to guarantee them the runners-up spot to Ireland.
But defeat could consign them to a fifth-place finish for a second straight tournament, depending on the day's earlier results.
And if last year's match is anything to go by, it could be a late finish...
England v Ireland (14:45 GMT)
The grounds staff at Twickenham have painted some lovely blue lines on the turf after snow was forecast in London.
But there's no sign of any white stuff on the pitch at the moment.
Image source, BBC Sport#bbcsixnations or text 81111
Ralph Brooker: Come on @EnglandRugby, external. It’s payback time. Faz with an 80+ minute drop to win.
Unlikely, Ralph. But it would be a fine finish!
Spoiler alert!
Ireland have already won the Six Nations title.
And England fans might want to look away now...
Here's the table as it stands before the final round of fixtures in this year's Championship.
Image source, BBC SportRight, England against Ireland might be the 'big' game of the day, but we've got two other matches to offer you.
Italy v Scotland kicks off at 12:30 before Wales take on France at 16:45.
And there's still plenty to play for.
England v Ireland (14:45 GMT)
Fans are already arriving at Twickenham ahead of the 14:45 kick-off.
They're eager. But clearly confused about who to support.
Image source, BBC SportEngland v Ireland (14:45 GMT)
Hot off the press, we can show you today's match programme at the Aviva Stadium.
It features an interview with Johnny Sexton on his British and Irish Lions team-mate Owen Farrell.
"We've got a good relationship," says Sexton.
"Apart from trying to kill each other at the Aviva last time, we get on great."
The two Lions will presumably be at each other's throats again this afternoon in Dublin...
Image source, BBC SportEngland v Ireland (14:45 GMT)
Let's all just remember that Ireland wouldn't have been in this position without one extraordinary, other-worldly strike from Johnny Sexton.
On the opening weekend in Paris, with the clock in the red and the rain pelting down, Ireland kept the ball for 41 cool-headed, clear-eyed phases before Sexton executed one of the best drop-goals anyone has ever seen.
And Ireland won the game 15-13. Match one - tick.
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How are you celebrating St Patrick's Day? Have your celebrations begun already?
Will Ireland win the Grand Slam and who will steal second place? Do we even care?
This is your last chance to get a photo of your dog, rabbit, sofa, child, breakfast table, uncle, grandma, wife, husband or fish featured on the BBC Sport website before next year's Six Nations.
Tweet me on #bbcsixnations or text 81111.
England v Ireland (14:45 GMT)
Joe Schmidt's Ireland side wrecked England's Grand Slam bid 12 months ago with a 13-9 win in Dublin on the tournament's final weekend.
It was also the first defeat of Eddie Jones' reign as England head coach as his side had to settle for retaining the Six Nations title.
Ireland already have that won, so it's all or nothing at Twickenham this afternoon.
And England are out for revenge.
England v Ireland (14:45 GMT)
Image source, BBC SportCan Ireland make it three Grand Slams?
Victory over Eddie Jones' side at Twickenham this afternoon would see Joe Schmidt's side emulate the teams of 1948 and 2009.
But will England exact revenge for last year's defeat in Dublin?
And of course...
Happy St Patrick's Day!
Image source, Getty Images
Image source, Getty ImagesAnd here's how you can watch, listen or follow on the BBC.
A whole seven hours of live coverage. Whoopee.
Italy v Scotland - BBC Radio 5 live sports extra, BBC Radio Scotland
England v Ireland - BBC Radio 5 live
Wales v France - BBC One, BBC Radio 5 live sports extra, BBC Radio Wales and BBC Radio Cymru.
Right, let's run through the timings on the final day of the 2018 Six Nations.
Pens at the ready...
As final days go, it was pretty epic.
So it's a good job we've got another show-stopping Saturday in store this year.
Saturday, 18 March 2017.
Image source, Getty ImagesScotland kicked us off with an easy victory over Italy at Murrayfield as their visitors collected another wooden spoon.
Image source, Getty ImagesWales lost to France in the final seconds of a farcical 100-minute match as sporting lines became blurred.
Image source, Getty ImagesAnd there were muted scenes in Dublin as England won the Six Nations title but were denied a Grand Slam by Ireland.