Pregnant Madeline Holtznagel steps out in a blue bikini as she joins Justin Hemmes for lavish Boxing Day yacht party near their $100m mansion

Madeline Holtznagel and Justin Hemmes celebrated Boxing Day in style as they hosted a luxury yacht party for their friends in Sydney.

The couple, who are expecting their first child together, put on a sweet show as they cuddled aboard his $320,000 TechnoHull Sea DNA 999 speedboat.

Madeline, 27, looked beach-ready in a stylish blue bikini, consisting of a low-cut strappy top and high-waisted thong bottoms with floral details.

She protected her eyes with oval sunglasses from Miu Miu and carried her essentials in a straw handbag for the sun-soaked day out at sea.

Madeline at one point placed her hand on her pregnant belly as she stepped out, just weeks after her baby news was first revealed.

After boarding the lavish boat, Madeline cozied up to Merivale boss Justin, 52, as she wrapped her arms around him in a sweet moment.

Madeline Holtznagel and Justin Hemmes celebrated Boxing Day in style as they hosted a luxury yacht party for their friends in Sydney

The couple, who are expecting their first child together, put on a sweet show as they cuddled aboard his $320,000 TechnoHull Sea DNA 999 speedboat.

The couple, who are expecting their first child together, put on a sweet show as they cuddled aboard his $320,000 TechnoHull Sea DNA 999 speedboat.

Pregnant Madeline, 27, looked beach-ready in a stylish blue bikini, consisting of a low-cut strappy top and high-waisted thong bottoms with floral details

Pregnant Madeline, 27, looked beach-ready in a stylish blue bikini, consisting of a low-cut strappy top and high-waisted thong bottoms with floral details

Justin showed off his toned body as he went shirtless in black board shorts as he hosted their friends on his speedboat for the Boxing Day festivities.

The group was spotted boarding the luxury ship near Justin’s $100 million Vaucluse mansion, where he and Madeline plan to raise their unborn child.

One of Justin’s friends has moved out of the eight-bedroom complex – which has been in the Hemmes family for more than 40 years – to make room for the baby.

Justin, who has a net worth of $1.39 billion, already has daughters Alexa, nine, and Saachi, eight, with his ex-girlfriend Kate Fowler, who he split from in 2018.

The business mogul started dating Madeline the following year, when the model was 22 and he was 47.

It was a huge step for the couple when their baby news emerged last month, with sources telling Ny Breaking Australia they were about to welcome their first child together.

Justin and Madeline’s reps told Ny Breaking Australia at the time that the couple will not be making an official comment.

They’ve been spotted together in recent weeks looking as in love as ever and most recently attended Pilates queen Bernadette Fahey’s wedding to Jordan Sukkar.

She protected her eyes with oval sunglasses from Miu Miu and carried her essentials in a straw handbag for the sun-soaked day out at sea.

She protected her eyes with oval sunglasses from Miu Miu and carried her essentials in a straw handbag for the sun-soaked day out at sea.

Madeline at one point placed her hand on her pregnant belly as she stepped out, just weeks after her baby news was first revealed

Madeline at one point placed her hand on her pregnant belly as she stepped out, just weeks after her baby news was first revealed

After boarding the lavish boat, Madeline also got cozy with Merivale boss Justin, 52, as they shared some sweet moments together.

After boarding the lavish boat, Madeline also got cozy with Merivale boss Justin, 52, as they shared some sweet moments together.

Simone Holtznagel's younger sister Madeline carried a beach towel in one hand as she soaked up the rays

Simone Holtznagel’s younger sister Madeline carried a beach towel in one hand as she soaked up the rays

Madeline appeared to be in good form as she smiled and waved to her friends as she greeted them at the seaside

Madeline appeared to be in good form as she smiled and waved to her friends as she greeted them at the seaside

Madeline accessorized her ensemble with a dainty gold chain and appeared to be in good spirits as she smiled and laughed with her friends

Madeline accessorized her ensemble with a dainty gold chain and appeared to be in good spirits as she smiled and laughed with her friends

Madeline's baby news emerged last month, with sources telling Daily Mail Australia they were about to welcome their first child together

Madeline’s baby news emerged last month, with sources telling Ny Breaking Australia they were about to welcome their first child together

Justin showed off his toned body as he went shirtless in black board shorts as he hosted their friends on his speedboat for the Boxing Day festivities

Justin showed off his toned body as he went shirtless in black board shorts as he hosted their friends on his speedboat for the Boxing Day festivities

The Merivale boss was seen cooling off with a dip in the sea as he made the most of the balmy temperatures

The Merivale boss was seen cooling off with a dip in the sea as he made the most of the balmy temperatures

The group was spotted boarding the luxury ship near Justin's $100 million Vaucluse mansion, where he and Madeline plan to raise their unborn child.

The group was spotted boarding the luxury ship near Justin’s $100 million Vaucluse mansion, where he and Madeline plan to raise their unborn child.

They all seemed to be having the time of their lives as they celebrated the Christmas season in style

They all seemed to be having the time of their lives as they celebrated the Christmas season in style

Justin has a net worth of $1.39 billion and is considered Australia's hospitality king, with more than 80 locations and billions in assets under his purview as CEO of Merivale

Justin has a net worth of $1.39 billion and is considered Australia’s hospitality king, with more than 80 locations and billions in assets under his purview as CEO of Merivale

Justin and Madeline quietly started seeing each other in 2019 and even sparked engagement rumors last year when fans spotted the model with a ring (pictured)

Justin and Madeline quietly started seeing each other in 2019 and even sparked engagement rumors last year when fans spotted the model with a ring (pictured)

Justin and Madeline quietly started seeing each other in 2019, a year after his debut on the Financial Review Rich List with an estimated net worth of $951 million – which has since risen to $1.39 billion.

Although they generally keep their romance under wraps, the couple is often seen disembarking from his seaplane after enjoying a luxurious family vacation with his two daughters.

The couple has gone from strength to strength since going public and even sparked engagement rumors last June.

Eagle-eyed fans noticed Madeline was wearing a ring on her wedding finger as they wondered if Justin had popped the question.

One photo showed her wearing the jewelry as she cuddled up to Justin as they enjoyed a bowl of Udon noodles together at a restaurant in Japan.

But the bling appeared to be an emerald and diamond promise ring, and another photo showed her wearing another ring on the same finger as she posed for a selfie.

Justin is considered Australia’s hospitality king, with more than 80 locations and billions in assets with names like the Ivy, Queen Chow and Establishment under his purview as CEO of Merivale.

He is the only son of Merivale Group founder and nightclub magnate John Hemmes and Justin took over the company after his father’s death in 2015.