The ad is intended to air 25 times on CNN and 25 times on Fox, from this Friday until Monday.
The theme of the ad, from an early copy I've seen, is that Donald Trump is too offensive, that Hillary Clinton wants higher taxes and bigger government** (both supported via clips of the major party's candidates) and that "America deserves better."
Johnson is said in the ad to be for "tolerance, free enterprise, and a sane foreign policy." He wants "government that stays out of your pocketbook, and out of the bedroom."
The $1 million for the ad buy, I'm told, is coming from Jeff Yass, an options trader and one of the founders of Philadelphia-based Susquehanna International Group.
Yass had previously been generously supporting Rand Paul SuperPACs. He'd given six figures to America's Liberty PAC, $300,000 to Concerned American Voters, and a previous million to PurplePAC last year when it was still supporting Rand Paul in his Republican primary.
UPDATE: What seems to be the finished ad, slightly different from the earlier version I saw.
**The particular attack on Clinton switched from higher taxes and bigger government to "will say anything to get elected" and hit the email controversy