Park Agencies UK has announced a number of Godzilla: King Of The Monsters t-shirts as well as other Godzilla t-shirts. All shirts are officially licensed, are available in sizes from S to 5XL, are 100% cotton, retail for approx $18 to $22 US, and are currently available on Amazon UK. Check them all out right here. 
Update: a few new designs have been added, also totes and hoodies are now available with some of the designs.