Australia captain Aaron Finch won the toss and elected to field against England as both sides altered their line-ups for the third Twenty20 international at Southampton on Tuesday.
The hosts, now led by Moeen Ali, made two changes from the side that defeated the tourists by six wickets at the Ageas Bowl on Sunday to go an unbeatable 2-0 up in a three-match series.
Home captain Eoin Morgan was ruled out with a finger injury suffered in the second match and Jos Buttler, who made a match-winning 77 not out on Sunday, was not playing for personal reasons after being allowed to spend time away from the bio-secure 'bubble' with his family.
Their places were taken by Kent batsmen Sam Billings and Joe Denly, with Tom Banton set to open in place of Buttler and Jonny Bairstow now the home side's wicketkeeper.
With skipper Morgan and Buttler ruled out, all-rounder Moeen took over as captain.
"It's an absolute honour to captain your country and lead such a side," Moeen told Sky Sports at the toss.
"I enjoy the captaincy at Worcestershire -- it keeps you in the game and there is the responsibility," he added.
"This is obviously a different kettle of fish against the No 1 side in the world. I don't think I will be as good as Eoin but he produces other leaders so hopefully I can use his experience."
Australia made three changes, with wicketkeeper-batsman Matthew Wade set to open in place of David Warner and take over behind the stumps from Alex Carey.
All-rounder Mitch Marsh also came into the side, with Josh Hazlewood replacing fellow fast bowler Pat Cummins.
"All in all we've done some really good things, we just have to look more at those positives than the negatives," Finch told BBC Radio at the toss.
"The next 12 months are going to be pretty brutal so we're taking the chance to rest some guys," the opener added.
Whichever side wins this match will top the T20 international rankings, with England narrowly ahead of their arch-rivals following their wins in the first two matches.
England, the 50-over world champions, conclude their home international programme this season with three one-day internationals against Australia in Manchester starting on Friday.
England: Tom Banton, Jonny Bairstow (wkt), Dawid Malan, Sam Billings, Moeen Ali (capt), Joe Denly, Chris Jordan, Tom Curran, Adil Rashid, Jofra Archer, Mark Wood
Australia: Aaron Finch (capt), Matthew Wade (wkt), Marcus Stoinis, Steve Smith, Glenn Maxwell, Mitchell Marsh, Ashton Agar, Mitchell Starc, Kane Richardson, Adam Zampa, Josh Hazlewood
Umpires: Alex Wharf (ENG), Martin Saggers (ENG)
TV umpire: David Millns (ENG)
Match referee: Chris Broad (ENG)