Really showing approval about current king climbing (2,7)

I believe the answer is:

no kidding

'really' is the definition.

'approval about current king climbing' is the wordplay.
'approval' becomes 'nodding'.
'about' is an insertion indicator.
'current' becomes 'i' (symbol for electric current).
'king' becomes 'k'.
'climbing' is a reversal indicator (in a down clue, letters climb up).
'i'+'k'='ik'
'ik' written backwards gives 'ki'.
'nodding' enclosing 'ki' is 'NO KIDDING'.

'showing' is the link.

I've seen this clue in The Telegraph.

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