Robbie Williams is "blasting Black Sabbath music" to torment his rock star neighbour Jimmy Page over their bitter home extension row, according to a complaint to their local council.
The Take That singer won a five-year battle when he was granted conditional approval last year to build a basement swimming pool at his London home.
Mr Page fears excavation work will damage his 1875 Grade-I listed mansion.
Mr Williams is also said to be imitating Page's former bandmate Robert Plant.
A letter to the Royal Borough of Kensington and Chelsea states that as well as Sabbath, the singer has been playing Pink Floyd and Deep Purple songs at high volume, as "he knows this upsets" the 75-year-old Led Zeppelin guitarist, who has lived at Tower House for more than 46 years.
The two stars live next door to each other in Holland Park - Mr Williams's Grade II-listed home used to belong to film director and restaurant critic Michael Winner.
It is not publicly known who wrote the complaint, which is signed "Johnny".
Talking about the row in the Telegraph on Friday, a spokesman for Mr Williams said the claims in the complaint were "a complete fabrication and nonsense".
The correspondent adds that Williams has also dressed up to imitate Mr Plant by "wearing a long hair wig, and stuffing a pillow under his shirt in an attempt to mock or imitate Mr Robert Plant's beer belly that he has acquired in his older age".
This is "embarrassing", the letter continues, because "Mr Plant was remembered for performing with his shirt open on stage, and obviously he cannot perform in his current condition as it would be very embarrassing".
In December, planning permission for the extension to be built was granted to 44-year-old Mr Williams.
However, work cannot begin on his Kensington home until councillors receive reassurance that vibration levels and ground movement issues will be monitored.
They will also decide whether to ask Mr Williams for a bond, which could be forfeited if those conditions were breached or if any damage is done to Mr Page's property.