Martha Kalifatidis, a participant of Married at First Sight Australia, surprised fans when she shared a video of herself breastfeeding her fiancé Michael Brunelli.

The couple, who appeared on the 2019 season of the show, posted a strange video in which Michael is seen suckling on Martha's dry breast.

Despite having no prior knowledge about each other, the couple has become a success story of the reality show, which matches couples.

Martha and Michael were among the couples who decided to stay together after exchanging their final vows, and they announced their pregnancy in September of last year.

Earlier this year, the couple welcomed their little boy, named Lucius.

On Thursday (March 23), the couple, who are both 34 years old and new parents, shared a surprising video on Instagram where Michael attempts to alleviate a blockage by suckling on Martha's breast.

While he was sucking, she joked: "You've got to breathe through your nose. It's like giving a b***job, you've really got to focus on the breathing more than any other part of it."

Once he comes up for air, Michael says:

The on-screen text also displays: "[Your] nipple's all the way down my f***ing oesophagus."

The text overlay also reads: "Blocked milk duct... it's a team effort," while the caption says: "So this was a new experience..."

Fans are finding it hard to process the video, and one individual commented: "I think you've reached a new level of over sharing," alongside a laughing emoji.

"Some things you just don't need to share," said another, while a third added: "Yuk why would you post this."

And a fourth wrote: "So wrong on many levels.. Certain things should be kept private there are porn and fetish sites for this type of thing."

Nonetheless, some viewers appreciated the couple's honesty and authenticity regarding first-time parenthood challenges.

One person said: "Michael you are a legend! The love you both have for each other is just so heart warming."

Another wrote: "The amount of times my partner has to do this! Thank you for making me feel normal."

"If anyone takes offence to this - you need to grow up."

While a third added: "This is the most real post I've seen on social media in a while."

"Just remember - breasts are apart of a woman's body simply to nurture our children, in the healthiest and most natural way possible. Yet unfortunately breast have been sexualised."

"So if you find this post weird, you're probably one of them who sexualises the women's anatomy, instead of seeing it as beneficial, nurturing, comforting and natural."