Anne Hathaway is laughing off rumors that she's pretending to be pregnant. 

On Monday, the 43-year-old actress took to Instagram to subtly address claims that her baby bump is 'fake,' after a 'ridiculous' maternity outfit she wore on Sunday went viral. 

She wrote in the caption of a behind-the-scenes video montage: 'Fake hair, real bump. Enjoy The End Of Oak Street Block Party chaos with me as my outfit literally melts in the heat!!'

In the footage, the Oscar winner is surrounded by a glam squad, including a stylist seen securing a hairpiece to add volume to her ponytail, as she admits: 'It's not my hair.'

Hathaway attended the Los Angeles premiere of her latest film The End Of Oak Street over the weekend, where she bared her midriff in a cropped top and low-waisted jeans after announcing this summer she and husband Adam Shulman are expecting baby number three.

Fans went wild on TikTok, with a slew of comments accusing her of wearing a prosthetic bump.

'Why does it look fake?' asked one internet user, with the comment collecting nearly 6,000 likes.

Another person added, 'It does look fake. There’s body makeup on it.'

Others came to Hathaway's defense, explaining her stomach looks different than other pregnant women's because she's in great shape.

'It looks different because she was already fit and probably continues to work out, so she is all muscle and baby!' said one fan.

And someone else commented on the star's Instagram post, 'The fact that other women were questioning her literal pregnant belly because "mine didn't look like that" is so strange to me.' 

The actress had been trolled for modeling a custom baby blue high-low Prabal Gurung halter top made of silk and boasting a floor-grazing train with low-rise jeans from La Ligne's Jenny. 

One critic wrote online that the outfit 'looks ridiculous', another shared, 'This one is so wrong, sorry,' and a third exclaimed, 'Jeans? JEANS?! That dazzling top deserves a better companion'.

Hathaway hit headlines earlier this summer when she announced she was expecting her third child at the age of 43.  

Hathaway shares sons Jonathan, ten, and Jack, six, with Shulman, whom she wed in 2012. 

While appearing on Late Night with Seth Meyers in July, she got candid about her pregnancy.

'I mean, we knew what we were doing, but we were so shocked it worked!' she said about finding out she was with child. 

'We were so shocked it went this way', the actress echoed about her and her husband's surprise at their baby news.

She described the pregnancy as a 'buzzer beater'.

And remarking on becoming pregnant in her 40s, she recently told Access Hollywood: 'There’s always hope until there’s not, but when you get to a certain age, that hope looks like 1 per cent to 2 per cent.

'So we just decided to see where life took us, with a very, very healthy, realistic expectation, which was very low.'

Hathaway shared, 'We’re overjoyed because we just know from personal experience that not everybody gets this, and certainly not when you want it – sometimes not ever.'