The best play technically is to lead the ace first, this only loses two tricks if West has KJx or KJxx.

However, consider playing a small card from dummy.  If East will play the king from Kx this is a better play.

In the Crockfords final of 2000 a well known English international tried playing small from table, Steve Eginton sitting East ducked smoothly from Kx and declarer lost two tricks in the suit.

This was enough for the Manchester team of Michelle Brunner, John Holland, John Hassett, Bill Hirst and Howard Melbourne to win the event in a very tight finish.