Egyptian goddess is appearing twice (4)
I believe the answer is:
isis
'egyptian goddess' is the definition.
(I've seen this before)
'appearing twice' is the wordplay.
'appearing' becomes 'is' (I can't explain this - if you can you should give a lot more credence to this answer).
'twice' says to double the letters.
'is' doubled is 'ISIS'.
'is' is the link.
Can you help me to learn more?
(Other definitions for isis that I've seen before include "River Thames at Oxford" , "Wife of Osiris" , "Oxfordshire river" , "To be, to be an Egyptian goodess" , "Mrs Osiris" .)