Minds immediately boggled at the thought of the Opposition questioning the Prime Minister about his love life. And then - for decorum's sake - they just as quickly stopped boggling.
It is Key's occasional goofiness which makes him such a dangerous opponent, however.
Some Labour MPs still find it difficult to take him seriously. Earlier in question-time, the
Opposition got a lesson in just how deadly serious Key can be.
With National being battered on several fronts, Key came down to the House with the intent of getting his party back on the front foot in Parliament at least.
In his sights were the Three Musketeers, the (very) loose Opposition troika of Shearer, the Greens' Russel Norman and NZ First's Winston Peters.
Shearer was the first to cop it. He asked Key if it was correct that under the provisions of just-introduced legislation covering the part-sale of state-owned enterprises like Genesis Energy, "half a dozen foreign investors'' could legally purchase all the listed shares.
"No,'' Key replied firmly before adding that no-one would be able to hold more than 10 per cent, that six times 10 was 60, and the Government was retaining 51 per cent.
It was the equivalent of the maths teacher handing a pupil the dunce's hat and telling him to go and stand in the corner.
Next up was Peters. His questioning of how Key expected to get a majority to pass the legislation setting up the "mixed-ownership model'' was abruptly cut short by Key holding aloft a copy of the prospectus for the 1998 share float in Auckland Airport "signed off by the then Deputy Prime Minister and Treasurer, the Rt Hon Winston Peters''.
Knowing he was beaten, Peters could only smile - and, for once, in silence.
As the cheers of National MPs subsided, Norman tried a different tack, querying how the Prime Minister could possibly believe he had a mandate for asset sales when opinion polls showed 60 per cent-plus opposition to National's partial privatisation plans.
Key, however, suggested there was a difference between an electoral mandate and what a poll might say - a difference which the Greens not so long ago had been very happy to exploit.
Key recalled that it was the the Greens who initiated the legislation banning the smacking of children despite the polls showing most people were vehemently opposed to any change.
Key did not have to say any more. It was game, set and match. The three Opposition leaders had been routed - at least until the next time.