Went on Aegean site and found this

Extra baggage allowance*
As a Gold member you can choose not to travel light. We allow an additional 20 kg (44 pounds) where the weight concept applies, or one additional piece of luggage where the piece concept applies.
* This benefit may only be available if traveling on two or more Star Alliance member airlines on a single ticket. Please contact the Star Alliance member airline with whom you will check-in with for further details.

Still not clear, and I don't want to phone TK and ask so as not to give them any ideas, but I don't want to be slapped with overweight charges on my next trip to Asia.