The Block's Haydn Wise and his wife Chelsea announce they're expecting their second child

The Block's Haydn Wise and his wife Chelsea have announced they're expecting their second child.

The birth of the couple's first child occurred during the first week of filming of Australia's favourite home renovation show.

The series saw Haydn, who is competing on the current season with his best friend Ricky Recard, flown out of Phillip Island by helicopter for the birth of his daughter.

The series wrapped up filming in June and now the Victorian couple have revealed baby number two is already on the way.

'Within the first month of him returning home it happened. Everyone's a little but shocked. I guess when it rains, it pours,' Chelsea, 36, told Now to Love .

The expecting mother told the publication she is now 14 weeks pregnant.

'Haydn and I were kept apart, as you know, with The Block for a period of time, so the reunion was lovely,' she said.

An early teaser for Nine's 20th anniversary season showed Chelsea's early delivery via C-section throwing bathroom week into chaos.

The preview showed Blockhead Haydn getting an emergency call from his partner just as things on the building site were heating up.

After learning his wife was 'going into early labour', the Melbourne IT manager appeared to be astonished by the news.

While Haydn was left visibly shocked, host Scott Cam was clearly delighted with the news of a 'Baby Blockhead'.

'I'm gonna be an Uncle,' he exclaimed.

The pregnancy announcement comes after the couple told Woman's Day that they had undergone rounds of IVF , their last cycle early last year, before their daughter Matilda was conceived naturally and came along five months ago.

'We thought there was no chance we would ever be parents,' Haydn explained.

'She's 100 per cent a miracle,' Chelsea, 36, told the publication at the time, adding that the tot came via emergency C-section in March.

'We'd been trying for nine years and we knew pretty quickly we weren't going to have one naturally, or we didn't think we were, so we went through the IVF process,' Haydn said.

'That went on for a number of years, then we had Covid in between and it paused, and then we gave up'.

The pair refer to little Matilda as a 'unicorn baby' and couldn't be more happy with their little family.

'We didn't expect it to happen so quickly, given our previous struggles,' Chelsea continued. 'But we had heard it can happen quite quickly after the first one'.

The second baby is due on March 29, 2025.

That means Tilly will become a big sister just days before her own first birthday.