Nicola Sturgeon has encouraged people in England to vote for the Green party in May's general election.
Speaking at an event at the London School of Economics, the first minister told an audience of academics and journalists that her vote would go to the Greens or Plaid Cymru if she lived outside of Scotland.
"If you live in Wales I'd advise you to vote for Plaid Cymru; if you live in England I think there's an argument for voting Green," she said.
"I'm a progressive politician. In Scotland that means vote SNP without a shadow of a doubt. I want to see as many progressive voices in the House of Commons after the election – that is SNP, Green, Plaid Cymru."
The idea of the SNP standing outside of Scotland was raised last year, but was voted down by the party. Instead, the first minister has spoken of a "progressive alliance" between the SNP, the Greens, and Plaid.
She said voting Labour would only be the right choice if the candidate is progressive and is prepared to challenge the party leadership.
Sturgeon appeared to be less keen on the Greens than Plaid, stating she would "probably be looking" at voting Green in May if she lives in England, but would "definitely" vote Plaid in Wales.
"So that's my advice, take it or leave it," she said.
"But if you live in Scotland, definitely vote SNP."
Jamie Ross is a Scotland reporter for BuzzFeed News and is based in Edinburgh.
Contact Jamie Ross at firstname.lastname@example.org.
Got a confidential tip? Submit it here.