Lily Allen is pregnant.

The "Smile singer and husband Sam Cooper - who became parents to daughter Ethel Mary last November - are said to be "thrilled" at the news they "will welcome another child into the world in December.

"Lily has started telling her friends and everybody in her close circle is so excited for her. It was a surprise but Lily and Sam are thrilled. The pair of them have loved every minute of parenthood so far and wanted to expand their brood quickly. So it's great timing," a source told the Sunday Mirror.

Friends admit to being shocked by the news but couldn't be happier for the couple, who married in June 2011 after two years together. "I think everyone is a bit surprised they've decided to have another baby so quickly. But they are great parents and absolutely devoted to Ethel. The pair of them are just delighted they've got another one on the way. They're such a happy family with Ethel. This is really great news," one friend said.

The 25-year-old star is said to be surprised people hadn't already guessed her happy news as her figure has already noticeably changed shape. "Lily was sure people were going to cotton on to the fact she had a pregnancy bump but she seemed to get away with it thanks to wearing very baggy clothing. Her bump has popped out very early - far earlier than the last pregnancy. She's been joking she feels six months pregnant already," a source said.

Almost two years ago, Lily and Sam, 34, were left devastated when they lost their baby six months into the singer's pregnancy. In 2008, the brunette beauty - who recently confirmed she was returning to her pop career - suffered a miscarriage while dating Chemical Brothers star Ed Simons.