The 42-year-old actor and his wife, 'Harry Potter' actress Helen McCrory, are furious over plans to erect a large new home next to St Christopher's School in Belsize Park, where their six-year-old daughter Manon is a pupil, reported Daily Star.
Protesters claim the building work will be disruptive for the school and the new structure, which will feature a two-storey basement complex and a swimming pool, will overshadow the playground.
Lewis and McCrory joined other concerned parents at a planning hearing to object to the proposal.
McCrory insists she is pleased the campaign has attracted so many supporters.
"It's amazing. You have hundreds of people complaining because someone wants to build a (house and a) swimming pool," she said.