Mobile network operator O2 has pledged to fund the men's and women's games equally after signing a new five-year deal with the Rugby Football Union.
The new agreement begins in September 2021 and is reportedly worth £7.5m per year, extending its time as principal shirt sponsor into three decades.
England's RFU said in July it faced short-term losses of up to £107m.
"O2's commitment to equally support both our elite teams is commendable," RFU chief executive Billy Sweeney said.
The announcement will be welcome news for the governing body, which called for a government bailout last month, after suffering huge financial losses as a result of the Covid-19 pandemic.
With all of the autumn's matches and the entire 2021 Six Nations set to be played behind closed doors, the RFU has forecast a £138m reduction in revenue and losses of £60m.
It has made 140 redundancies in an attempt to ease its financial crisis.