Partick Thistle have accepted "an extremely generous offer" to fund a legal challenge to their relegation from the Scottish Championship.
And the Jags will join Hearts in court action, after the Tynecastle side were demoted from the Premiership.
Thistle previously said they could not afford the six-figure legal costs.
However, an offer to fund court action means they will "launch a joint legal challenge to resolve what others have failed to do since April".
The SPFL's reconstruction proposal - which would have reversed the demotions of Thistle, Hearts and Stranraer - failed after only 16 of the 42 clubs backed it. All four senior divisions were curtailed because of coronavirus.
Thistle had said on Monday they would seek "justice" on the pitch rather than through the courts.
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"Yesterday, we said that court action was our preferred route to challenging our relegation to League One," chairman Jacqui Low said on behalf of the board. "It was only a lack of funding that stopped us. At that time, we reserved the right to change our position should circumstances change.
"Last night, in response to our statement, we received a proposal to fully fund legal action should we wish to pursue it, at no cost to Thistle. After careful board consideration, we have now accepted this extremely generous offer of unexpected help.
"To those who think we should just move on and accept what's been dished out to us, yesterday 26 clubs put themselves first. Today, we have now been given the opportunity to do the same."
Meanwhile, Peterhead say chairman Rodger Morrison "has been left bemused by the failure" of the SPFL's 14-10-10-10 league restructuring proposal.
"We voted for the change and I still believe that it was the right thing to do however not enough clubs felt the same and I find that really hard," said Morrison.