David Walliams surprised the pupils at Flakefleet Primary School with an impromptu reading from his new children's book - after making a dramatic arrival by helicopter.
The Britain's Got Talent judge and children's author used his golden buzzer to send the singing schoolchildren through to the live final during the first episode of this year's series.
Walliams, 47, said he "couldn't resist" paying them a visit to see how their preparations were coming along for the live show.
The boys and girls, aged five to 11, performed a choreographed routine to Don't Stop Me Now by Queen led by their headmaster Dave McPartlin during the first episode of this series.
He said: "He was so lovely with all the children and staff and had time for everyone, what an absolute gentleman.
The former Little Britain star is recognised as one of the most popular children's authors in a generation.
Britain's Got Talent Live Semi-Finals start Monday 7:30 on ITV.