I knew about this deal a few days ago but can finally reveal it.
PlayStation Plus subscriptions will be discounted by 25% from June 1 via the Playstation store. As this is a Days of Play promotion, you can expect the same discount to be available at retailers such as JB Hifi, Amazon and EB Games.
Good time to stock up!
Full credit to Bill-bill Kun –
I also note that this reduction of -25% is valid in all countries which offer the Playstation Plus. It is therefore a worldwide promotion (valid for example in Brazil or Turkey).