The Stone Roses bass guitarist and wife Imelda are said to have known about becoming parents before the band's live comeback in June.
However, they decided to keep the news a secret until she completed her first trimester, reports The Sun.
A source said: "They are absolutely overjoyed."
The 49-year-old musician - real name Gary Mountfield - reunited with The Stone Roses for a series of comeback gigs earlier this summer.
Michael Eavis recently said that The Stone Roses could headline next year's Glastonbury Festival.