Joseph, England's star performer at outside centre over the past year, has recovered from the chest injury that kept him out of last week's Pool A defeat by Wales and will be expected to add the cutting edge needed to unlock the Wallabies' defence.
"JJ is hard to replace and to have him back is a real positive," England head coach Stuart Lancaster told a news conference.
Defensive organiser Barritt, who looked short of his best against Wales, will be more comfortable in his usual position outside Saracens club mate Farrell.
Flyhalf Farrell had an exemplary game with the boot last week, scoring 20 points, to fend off the challenge of George Ford, who was named among the replacements, along with rugby league convert Sam Burgess.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Ben Morgan has also recovered from a knee injury to start at number eight, but lock Courtney Lawes is ruled out, allowing Joe Launchbury to start alongside Geoff Parling in the second row.
There is also a place on the bench for 37-year-old Nick Easter, who was drafted into the squad this week to replace Billy Vunipola after the big number eight was ruled out of the tournament with a knee injury.
George Kruis is in line for a first taste of World Cup action from the bench, selected by virtue of his ability to cover lock and back-row positions.
England had delayed naming their team to allow for a late fitness test on scrumhalf Ben Youngs, who suffered an ankle injury in the Wales defeat.
England, who have won four of the past five meetings between the two great sporting rivals, will almost certainly need to win to avoid going out at the pool phase.
"It’s a must-win game, there's no hiding away from where the accountability lies. The stakes are huge, of course, but the boys will be ready," Lancasater said.
"You can't spend your time thinking about the past or the future -- just have to nail down what's needed to win this game."
The situation will become clearer after Wales play Fiji later on Thursday, but only a shock Welsh defeat would give England a glimmer of hope should they lose on Saturday.
Wales and Australia meet at Twickenham in their final pool game on Oct. 10, followed by England's last match against Uruguay in Manchester.
England team:
1-Joe Marler, 2-Tom Youngs, 3-Dan Cole, 4-Joe Launchbury, 5-Geoff Parling, 6-Tom Wood, 7-Chris Robshaw (captain), 8-Ben Morgan; 9-Ben Youngs, 10-Owen Farrell, 11-Jonny May, 12-Brad Barritt, 13-Jonathan Joseph, 14-Anthony Watson, 15-Mike Brown.
Replacements: 16-Rob Webber, 17-Mako Vunipola, 18-Kieran
Brookes, 19-George Kruis, 20-Nick Easter, 21-Richard Wigglesworth, 22-George Ford, 23-Sam Burgess.
(Editing by David Goodman)
