Just over a year after welcoming their first child into the world, the 39-year-old and husband Brett Desmond have a new arrival on the way.
The Dundalk-born star was showing her blooming figure while out walking in Dublin city centre yesterday.
The notoriously private singer has reportedly told just a few friends about their new baby, due at the end of the year.
The couple's baby daughter Jean, born in April last year, was named after her mother, Jean Corr, who passed away in 1999. Andrea sold over 30 million albums with The Corrs before they took a break in 2006.
Andrea has insisted that, if she returns to music, it will be on her own terms as a mother.
"You don't really realise it until you have your own (child) the overwhelming love," she said.
"It's so rewarding. I don't want to go on the road and leave my daughter.
"I am a full-time mother. At the same time, there's still music to be made," she added.
Little Jean was born less than three years after Andrea married financier Brett Desmond, the son of billionaire businessman Dermot.
The couple married in a lavish ceremony in Co Clare in August 2009.
But it was in 2011 – while promoting her second solo album Lifelines – that Andrea admitted they were ready to start a family, saying: "I'm as ready as I'll ever be."
Motherhood clearly suits Andrea, who looked as gorgeous as ever while out and about in the city centre.
Andrea looked cool in a summers dress and flat sandals, with an oversized bag, while getting into a taxi on Baggot Street.
She has recently been tipped to replace Jessie J as a coach on the new series of The Voice, on BBC.