The 25-year-old singer – whose first child with boyfriend Sam Cooper is due in February – confided in pals after having an ultrasound scan to discover the gender of the tot.
A friend told The Sun newspaper: “Lily said she found out from a scan she is having a boy.
“She is really excited and can’t wait to give birth. She is always asking other mums about their pregnancies.”
The ‘Fear’ hitmaker – who is said to be looking into antenatal classes and yoga to help her through the next five months – is enjoying pregnancy but is struggling to contain her feelings of sickness and can’t stop drinking soup.
She told the Daily Mirror newspaper: “I could do with a great big cup of soup right now. Chicken, tomato – whatever I can get. That’s all I’ve really been craving.
“I could have it for breakfast, lunch and dinner. I’m serious – I just can’t get enough of it.
“The past few months have been a bit tough because I’ve been sick and stuff, but now everything’s fine, because I’ve discovered soups are the cure to my morning sickness.”
Lily – who suffered a miscarriage in January 2008 – recently admitted she spent much of her first three months of pregnancy terrified something would go wrong.
She said: “I had about a week and a half of really heavy bleeding and had to have lots of scans, that’s when I had to cancel my gig in Spain. I’ve been living in fear for the past three months.”