The 25-year-old singer, who was recently struck down with septicemia after suffering a miscarriage, has accused the Mail Online of breaching her privacy by running the photographs with the headline, 'Pregnant Lily spends £3m on stunning Cotswold home'.
According to The Guardian, Lily is also claiming the newspaper breached copyright laws by using the snaps.
'We have today issued proceedings on behalf of Lily Allen against Associated Newspapers [Daily Mail's parent company] for copyright infringement and breach of confidence,' said law firm Atkins Thomson, which is acting for Allen, in a statement. 'This action is in relation to an article published in the Mail Online on 14 September 2010.'
The star has previously been awarded damages after a French magazine falsely alleged she called Victoria Beckham a 'monster' and Cheryl Cole, 'stupid and superficial'.