A 23-year-old Sunshine Coast university student has spoken about taking his pregnant teenage cousin under his own roof to care for her and her newborn.

Tommy Connolly was contacted out of the blue by his 17-year-old cousin late last year, more than 10 years after they last met.

Homeless, illiterate and recovering from methamphetamine addiction, the girl told Mr Connolly she was pregnant and the baby’s father had been sent to jail.

He said he took her into his home without a second thought.

“I became the legal foster parent for her to make sure she’d keep the baby, stay off the streets and have a better life,” he wrote on Facebook.

“I've spent the last few months working, moving houses, having meetings with different departments, signing forms, being assessed and monitored, chasing funds, setting up her bank accounts, buying baby stuff, furniture, going to hospital/doctor appointments, and getting her settled in.”

An aspiring professional sprinter, Mr Connolly put his training on hold to work extra hours to support his cousin.

Mr Connolly even completed university assignments while the girl was in labour, before cutting the baby’s umbilical cord himself.

“She's the toughest girl I know,” he said.

“All she wants is for him to have a better life than she's had.

“There's still a long way to go, but things are on track and she has the opportunity she deserves.”

Mr Connolly shared this image online after the boy was born. (Facebook) (Facebook)

Mr Connolly’s brother Liam has set up a crowdfunding page to help pay for the costs to look after the baby boy and his mother.

“Both her parents were addicted to heroin, she had no clothes, no food, no shelter, and was pregnant with a child,” Liam writes on the page.

“Tommy doesn't tell like to tell people this but every week he puts away a little bit of money for our cousin and her baby so that eventually she will have enough to live on her own and take care of them both.

“[He] has stepped in and broken the cycle single-handedly but the road ahead will be difficult emotionally and financially.”

The call-out for help has already raised $4000 in just eight days, with a goal of $50,000 the target.

Liam says all money raised will go to the care of the little boy.

Mr Connolly thanked his work colleagues for their support and said helping his family was his main priority.

“When bad things happen, it's your family that supports you,” he wrote.

“It means no one gets left behind or forgotten.