Alistair Darling has taken the plunge and accepted a challenge from James McAvoy to take part in the ice bucket challenge.
The Better Together leader posted a picture of himself being drenched in icy water after he and Alex Salmond were nominated by the Scottish actor.
Now, the Scottish First Minister has also accepted McAvoy's challenge as the referendum campaign enters its final stage today.
Mr Salmond said: "I'm always up for any challenge, and I'm game for this one.
"It will invigorate me for the next month of campaigning - but the Scottish media should be careful what they wish for, as I get to nominate who's next for the ice bucket!"
The social media craze is aimed at raising awareness and money for the neurodegenerative disease ALS, or motor neurone disease.
Mr Darling thanked McAvoy and tweeted a link to www.gordonsfightback.com, an awareness-raising site set up by Better Together director of research Gordon Aikman.
Mr Aikman publicly revealed he is dying of the disease in a powerful article in the Scotland on Sunday newspaper in June.
In his video, X-Men star McAvoy said: "As it is the year of the Scottish referendum on independence, I'd like to nominate our political champions Alistair Darling and Alex Salmond to do their very worst."
As a bucket of icy water is poured over his head, he adds: "Alex, Alistair, you've got 24 hours."
McAvoy said he was nominated for the challenge by Chelsea manager Jose Mourinho.
Former US president George Bush, actress Gwyneth Paltrow and footballer David Beckham are among a host of well-known faces that have taken the plunge.
Russell Brand has already nominated Prime Minister David Cameron to try out the challenge, while President Barack Obama said he'd give the icy shower a miss but still donated money to the cause.
McAvoy, from Glasgow, has previously said he is "anti-political" when it comes to independence.
In an interview with The Scotsman in May, he said: "I will go with whatever way my country votes, but I don't know which way I want to go yet."
Mr Darling nominated the staff of Better Together to take up the dare next.
He said: "One of the good things about being the boss is you can nominate your staff for anything you want and tell them what to do - so I nominate the staff of Better Together.”