Great deal if you are an existing post paid Telstra customer.
Deal is for new or returning customers, so I believe you can cancel your account and take this up after your current billing has expired.
Log into your Telstra account and go to Offers to locate deal.
The code for this is TLS10DISC, which I just tested against an old Kayo account and it appeared to work, although I didn't go through to payment as I'm still on the beteasy deal, but worth a shot IMO:
https://forums.whirlpool.net.au/thread/35r5yx19?p=470#r9385