Love potion makes Duke of Edinburgh tango with the queen (7)
I believe the answer is:
Here is my best explanation:
'love potion' is the definition.
'philter' can be an answer for 'potion' (philter is a kind of potion). I am not sure about the 'love' bit.
'duke of edinburgh tango with the queen' is the wordplay.
'duke of edinburgh' becomes 'phil' (I can't explain this - if you can you should give a lot more credence to this answer).
'tango' becomes 't' (phonetic alphabet: alpha, bravo, charlie etc.).
'with' means one lot of letters go next to another.
'the queen' becomes 'er' (Elizabeth Regina).
'makes' is the link.