TVNZ presenter Alison Pugh reveals she's pregnant live on air

Jo Barus and Alison Pugh are expecting their first child together. Photo/Norrie Montgomery

She's kept her pregnancy news to herself for five months - even though Alison Pugh has suffered morning sickness so severe she fainted at work and was hospitalised.

Pugh announced that she was expecting her first child with fiance Jo Barus live while presenting TV One's Breakfast show this morning, news timed to coincide with an exclusive cover story and interview with Woman's Day.

Prime Minister John Key was on hand to congratulate Pugh, giving her with a kiss on the cheek and telling her: "You are glowing for a particular reason ... congratulations. Well done."

Key suggested the name 'Jonathan' would be a nice name for a boy - or 'JJ' for a girl.

But Pugh, 29, tells WD the pregnancy hasn't been plain sailing.

"Weeks seven through to 17 weren't great. And it was hard, because it wasn't like I could tell people why I was so poorly. But a few people probably cottoned on after the fainting."

Pugh suffered constant nausea and dizziness, and was admitted to hospital a month ago with acute migraines.

She also had trouble falling pregnant, saying she and Barus, a 40-year-old musician, had been trying for six months.

When she finally fell pregnant, she had to have a blood test after a faulty home pregnancy test gave her a false negative.

"We are so excited. So, so excited ... (Jo) came home that night with a huge bunch of flowers, a pink potted plant, a blue potted plant and a big sign that said, 'Is it a boy or a girl?' It was the sweetest thing."

Pugh said she waited five months to tell people because "I knew it would become everyone else's business".

"We thought, 'Let's just have it as our thing for a while.' But I'm really happy to be sharing the news now."

She also said she wanted to return to her job presenting Breakfast after the birth, and was keen to talk to Pippa Wetzell and Toni Street about how they "juggled a newborn and still did the crazy Breakfast hours".

- nzherald.co.nz