The ‘Hard Out Here’ singer weighed in on Instagram amid a backlash after the US Supreme Court voted to overturn a landmark 1973 law that gave pregnant women the right to choose abortion.
Posting on her Instagram Story, Allen, 37, said people should not have to justify terminating a pregnancy.
“I wish people would stop posting examples of exceptional reasons for having abortions,” she said.
“Most people I know, myself included, just didn’t want to have a f****** baby.
“AND THAT IS REASON ENOUGH! WE DON’T HAVE TO JUSTIFY IT.”
She went on: “It shouldn’t have to be said, and I think all these examples just play into the hands of the baddies.”
At the weekend, Allen performed at Glastonbury, joining singer Olivia Rodrigo on stage to perform her song 'F*** You' in response to the ruling.
Afterwards she said she was delighted that her daughters Ethel, 10, and nine-year-old Marnie “got to see their mamma play and slay Glastonbury with their favourite pop star”.
“They were very proud and so was I,” she said.
The singer shares her two children with her ex-husband Sam Cooper.
The pair tied the knot in 2011 but in 2018 it was announced that they had divorced and gone their separate ways.
Watch: Olivia Rodrigo and Lily Allen deliver message to Supreme Court during surprise Glastonbury performance