Celestia freed Nightmare Moon?

So someone asked Lauren Faust question about who's freed NMM from the moon. Answer is... Well, see for yourself:

I'm pretty sure that she means Celestia. Well, yeah. It makes some sense - I'm assuming that she really wanted to get her sister back. It also means that either she been one hundred percent sure that M6 really is Elements of Harmony or she had some backup plans. I really doubt that Celestia put entire Equestria on stake without any backup plans if something go pear-shaped. And... Celestia can control stars? Hah. So many argued that Luna can control stars because stars helped her escape the moon. But... yeah. "It's A Me, Celestia!".
And heck! It's also explained that line from SMILE book when SMILE agents said that NMM return just a cover-up.