Watch: AM host Melissa Chan-Green announces she's pregnant with second child

AM host Melissa Chan-Green has revealed live on air she is pregnant with her second child.

Joined on the show's couch by her three-year-old son Busby, Chan-Green asked him to help her with the announcement.

"Now Busby, we've been rehearsing something at home haven't we? We've been practising because mummy's had a little secret," she said.

"Do you want to say in mummy's microphone, what's mummy's secret?"

"Having a baby," Busby whispered.

The announcement led to cheers erupting in the studio.

"We're having a baby, another baby next year, so Busby you're going to be a big brother. That'll be so cool won't it, he's going to be a wonderful big brother," she said.

Chan-Green also revealed the lengths she had had to go to to fool viewers and the team about her pregnancy.

"I have been harbouring a little secret here on the couch, using my cards to try and conveniently hide what has been a growing little bump," she said.

"I've told Ryan but I hadn't told you when we were on air and I had to tell kind of a little white lie."

"You lied to me, that's what you did," fellow AM host Ryan Bridge said.

Bridge also told viewers there was a moment when the pregnancy was nearly accidentally revealed on air.

"All of us here at AM are so happy for you, that's very very cool. I know how much it means to you, how much it means to Caspar [Chan-Green's husband], but yes, there was a little moment wasn't there, where the secret was maybe nearly let out of the bag," he said, before playing a clip of the show from October 20.

"Some other exciting personal news here at the desk, but he's not going to tell you about it so I am... you've known for a little while, you didn't tell me," Chan-Green said.

"I have known for a little while... Ryan Bridge here has been nominated as a finalist for best news and current affairs presenter at the New Zealand TV Awards."

"I thought you were about to announce that you were having a baby or something," Bridge said in the clip from a month ago, much to the horror of Chan-Green. 

"My heart just went ba-boom," she said after the clip had aired.

"I felt your heart," Bridge said.

"It's funny, we sit next to each other all day and we don't think about this much, but we don't look at each other a lot because we're looking at the camera right, but I felt your stomach clench when you did that little laugh, so I had a strong suspicion from that moment I was onto something."

"We are super excited and feel very, very lucky," Chan-Green said.

Busby was born on November 21, 2019 with husband Caspar.