Up to 20,000 fans could be allowed into Twickenham to watch England play Barbarians on 25 October, the Rugby Football Union says.
It would be the largest crowd at a sporting event in the UK since lockdown restrictions were imposed in March.
Clearance to admit fans is subject to the obtaining of the relevant licence and approvals, including those from public health authorities.
The match was postponed in June because of the coronavirus pandemic.
Less than a quarter of Twickenham’s 82,000 capacity would be filled under the proposal.
The RFU is planning a number of safety measures to reduce the risk of the virus being transmitted in the stadium – with fans required to wear face masks except when in their assigned seats, or when eating or drinking, digital tickets only, as opposed to paper ones, and one-way systems to manage crowd movement.
England’s match against the Barbarians – for the Quilter Cup – takes place a day after the Premiership final and the weekend before the final round of Six Nations fixtures.
“This game will be an important start to the autumn for us,” England head coach Eddie Jones said.
The plan to admit fans was revealed on the same day that it was announced Arsenal hope to welcome supporters back to Emirates Stadium on a reduced capacity basis, starting from the Sheffield United game scheduled for Saturday, 3 October.
RFU chief executive Bill Sweeney said: “We continue to work closely with government and the local authority on the return of sports fans to the stadium.
“Local resident and spectator safety is our top priority and numerous measures are being implemented for the events that either adhere to or exceed the guidance provided by the government and the Sports Ground Safety Authority.
“A test event will be held to put into practice our operational plans and demonstrate that Twickenham Stadium is well prepared.”
‘There is massive interest in the Lions tour’
South Africa fans are being urged to apply for tickets for next year’s British and Irish Lions tour after the ballot opened on Wednesday.
Jurie Roux, South Africa Rugby’s chief executive, called for an ‘army of green’ to meet the ‘sea of red’ Lions fans.
An estimated 25,000 Lions fans travelled to New Zealand for the last tour in 2017, and it’s thought they outnumbered home fans in the final drawn test at Eden Park.
Despite the coronavirus pandemic, the next Lions tour is still scheduled to start on 3 July against the Stormers in Cape Town – with three Tests against South Africa set for 24 July, 31 July and 7 August.
Roux said: “More tickets will be available to home fans than to overseas fans.
“There is massive interest in the tour and we expect it to be a hugely popular occasion.”