The 48-year-old Nothing Compares 2 U singer's eldest son Jake and his girlfriend Lia welcomed a little boy on Friday (17Jul15).

O'Connor broke the happy news on Facebook.com by posting a cartoon which spelled out the words "It's a Boy".

Jake, 27, is the singer's son from her first marriage to music producer John Reynolds.

She alerted fans to the fact her son's girlfriend had gone into labour on Thursday (16Jul15), writing, "OMG! Am literally hours away from the greatest dream of my life coming true! #Granny! (sic). This for Lia and Jake and their little angel."

And she previously told fans, "Always wanted to be a granny. In fact that's the only reason I had kids (joking)."