The One Show host, 39, confirmed she has given birth to a baby boy, her first child with husband Charlie Thomson in a cute phone call.
“Well I do have some news I have a beautiful healthy baby boy,” she said as she called up to her show just three weeks into her maternity leave.
“We are absolutely delighted and we are completely in love with him. It’s the most wonderful feeling. 7lb 11oz – all very straightforward, it was lovely.
“Charlie was with me and my mum and dad were in the waiting room,” she added.
“The last four days have been heaven, we are in a little bubble the three of us.”
But Alex and Charlie hadn’t even thought of names and asked The One Show viewers to help her out.
“You know me, we’re a bit behind on the whole names, we didn’t know if it was a boy and a girl and we thought we’d know,” she said.
“We need some help, every time we help the One Show audience they come up with the goods and we’d like to see the suggestions.”
It comes just weeks after she bid an emotional goodbye to the BBC programme to go on maternity leave.
The 39-year-old was overcome with emotion as she prepares to become a mother for the first time.
While fighting back the tears, Alex said: “It’s the best team ever here and I’ll miss everyone very much.”
Alex was then handed a variety of gifts from guests Gary Barlow and Mel Giedroyc.
Co-host Paddy Kielty also presented the pregnant star with an usual gift.
Alex looked amused as she received a pack of personalised nappies with their faces superimposed onto the packaging.
Paddy said: “Now this was supposed to be cute – I didn’t realise how it was going to turn out.
Gary then offered some words of advice to Alex, telling her to make sure she invests in a high-quality camera so that she can take lots of great photos of the baby.
Alex will temporarily be replaced on the show by Michelle Ackerley and Angela Scanlonwhile she enjoys some time off with her baby.
It’ll be her first child with hubby of one year, Charlie Thomson.