It's a boy! Molly Sims reveals the gender of her third baby after breaking down about her fertility struggles

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She broke down in tears when revealing her fertility battles. 

But Molly Sims had happy news on Tuesday as she revealed the gender of her baby-on-the-way in December.

The 43-year-old shared the news on her blog that she's expecting a little boy, who will be her third child. 

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Having a boy! Molly Sims had happy news on Tuesday as she revealed the gender of her baby-on-the-way in December

Her son will will be a little brother to siblings Brooks Alan, 4, and Scarlett May, 19 months, and the trio revealed the news with a balloon filled box. 

The balloons were all blue in colour, and the family could not have looked more excited about their new addition. 

Brooks exclaimed he's 'going to have a baby brother' before launching into the Batman theme song. 

New addition: Her son will will be a little brother to siblings Brooks Alan, 4, and Scarlett May, 19 months, and the trio revealed the news with a balloon filled box 

Blue balloons: The 43-year-old shared the news on her blog that she's expecting a little boy, who will be her third child

Molly also explains in the video that Brooks has a sweet nick-name for his new sibling. 

He has named the baby 'Jack and the Bean Stalk-Batman,' she told the camera, and added that it’s been 'really sweet to see him so involved.'

The about-to-be-mom-of-three wore her blonde hair in loose barrel rolls, with a centre parting. 

Secret! Molly also explains in the video that Brooks has a sweet nick-name for his new sibling

Superhero sibling: Brooks has named the baby 'Jack and the Bean Stalk-Batman,' she told the camera, and added that it’s been 'really sweet to see him so involved'

Glamorous: The about-to-be-mom-of-three wore her blonde hair in loose barrel rolls, with a centre parting

Blue belly: 'This is a really special video,' she said excitedly

The showed their blue-paint covered hands which gave the game away

Cute: Molly explained her husband, 47-year-old producer husband Scott Stuber, was emotional when he learned he was having a second son

Ideas: The couple - who got married in 2011 - have already picked out a few names they like, but are waiting until they meet the little bundle of joy to make their final decision

'This is a really special video,' she said excitedly before Brooks nearly gave the game away eagerly. 

Molly explained her husband, 47-year-old producer husband Scott Stuber, was emotional when he learned he was having a second son. 

She said: 'When they first told my husband we were having a boy, I swear he almost started crying.'

The couple - who got married in 2011 - have already picked out a few names they like, but she said they are waiting until they meet the little bundle of joy to make their final decision.

She said: 'I love Wesley and Finley and Dutch and Wilder.'

Earlier she had shared a picture of her daughter holding her 'I voted' sticker, with social media followers. 

'We voted #letsdothis #shestolemysticker,' she captioned. 

Kneed votes: Earlier she had shared a picture of her daughter holding her 'I voted' sticker, with social media followers

The actress gave an emotional interview on her YouTube channel about her fertility issues, partnering with Us Weekly to share her family journey. 

Molly and Scott have a four-year-old son Brooks, 19-month-old daughter Scarlett and are expecting their third child together. 

The actress said she started considering children when portraying her pregnant character Delinda Deline on the NBC drama Las Vegas.

'I think playing pregnant on Las Vegas kind of tweaked me a little bit, in terms of I want this,' Molly said.

'The maternal clock all of a sudden started happening,' she revealed.

The former Sports Illustrated Swimsuit Issue model said she was ready to become pregnant with or without a partner.

'I decided to freeze my eggs before I met Scott,' Molly said.

She went through with the process after meeting her husband.

'We ended up freezing [embryos] about nine months before we got married in September of 2011,' Molly said.

Molly however got pregnant naturally with Brooks.

'Honestly I got pregnant on my honeymoon! I think because we had froze, and because I had in the back of my mind a safety blanket — a safety net — I got pregnant,' she said.

The couple tried IV twice and Scarlett was conceived before another round.

Molly is expecting her third baby in December and said it was a surprise pregnancy after five tests.

Family: She is expecting her third baby with 47-year-old producer husband Scott Stuber 

She got emotional talking about the 'dark moments' of trying to become pregnant and the dreaded 'didn't work' phone calls.

'Those are the worst,' Molly said wiping away tears.

'And that's the one thing I feel for all my friends that are going through this, to get that phone call,' she blubbered. 

She offered up some advice to others trying to cope with fertility issues.

'Try to have at least one person you can talk to and really be open with,' she suggested.

'There are a lot of dark moments … it’s sure not easy, and I got very, very lucky to find my prince and to have my family,' Molly added.