'I peed on a stick and I'm going to be a Mom!' Hills' star Whitney Port reveals she is pregnant with her first child

There must be something in the water.

Just a month after her pal and co-star revealed she was expecting, Whitney Port has announced she too is pregnant.

The 31-year-old star announced hers and husband Tim Rosenman's big baby news on Thursday.

Baby on board: Whitney Port revealed on Thursday she is expecting her first child with husband Tim Rosenman

The Hills star posted a snap of herself and her bump on Instagram Thursday afternoon.

Wearing just underwear in the picture taken by Cole Moser, the designer wrote: 'Oh hey! Just standing by the window in my underwear, with a BABY in my belly!!! 

While she said she and her husband of over a year are very excited, she joked she was not prepared for motherhood just yet.

Whitney said on Instagram: 'DM me if you know what I'm supposed to do with this thing for how ever many years I'm supposed to be in charge.'

Looking for advice: While she said she and her husband of over a year are very excited, she joked she was not prepared for motherhood just yet

Looking for advice: While she said she and her husband of over a year are very excited, she joked she was not prepared for motherhood just yet

Bump undercover: Whitney kept her baby news a secret under a sweater on Wednesday night at the TommyLand Tommy Hilfiger Spring 2017 Fashion Show

Bump undercover: Whitney kept her baby news a secret under a sweater on Wednesday night at the TommyLand Tommy Hilfiger Spring 2017 Fashion Show

The reality star turned Whitney Eve designer also posted a longer blog post about her pregnancy.

'When two people love each other so much and the love becomes too great to fit inside both people, it spills over into a THIRD person. This is how I am going to explain where babies come from to the little baby that is now growing inside my belly because Timmy and I are PREGNANT!'

The star said even she was a little shocked that she is having a baby. 

Keeping fans in the loop: The reality star turned Whitney Eve designer also posted a longer blog post about her pregnancy

Keeping fans in the loop: The reality star turned Whitney Eve designer also posted a longer blog post about her pregnancy

Surprise! The star said even she was a little shocked that she is having a baby, ''I peed on a stick and now I'm going to be a Mom!'

Surprise! The star said even she was a little shocked that she is having a baby, ''I peed on a stick and now I'm going to be a Mom!'

'I peed on a stick and now I'm going to be a Mom! Timmy and I were a bit shocked, but so excited to begin this journey. 

'It's been such an interesting and trying but amazing journey already. I can't wait to share my experience AND learn so much from all of you!

'I can't wait to be a Mom, but the fact that there is another person inside there is seriously crazy!'

Pregnancy cravings? Whitney and her husband Tim headed out for dinner last night after attending the fashion show

Pregnancy cravings? Whitney and her husband Tim headed out for dinner last night after attending the fashion show

And Whitney will certainly be able to be part of a pretty special moms' group as her Hills Co-star Lauren Conrad just announced last month that she is expecting too.

Their fellow MTV co-star Audrina Patridge welcomed her first child with husband Corey Bohan in June.

This time last year, Whitney told the DailyMail.com that she wanted to wait a little before she and her husband considered starting a family so they could enjoy being newlyweds.

Something in the water? Whitney will certainly be able to be part of a pretty special moms' group as her Hills Co-star Lauren Conrad (pictured Saturday) just announced last month that she is expecting too

Something in the water? Whitney will certainly be able to be part of a pretty special moms' group as her Hills Co-star Lauren Conrad (pictured Saturday) just announced last month that she is expecting too

Team mom: Their fellow MTV co-star Audrina Patridge (pictured 2007) welcomed her first child with husband Corey Bohan in June

Team mom: Their fellow MTV co-star Audrina Patridge (pictured 2007) welcomed her first child with husband Corey Bohan in June

The pair tied the knot in a perfectly Pintrest wedding in Palm Springs in November 2015.

The couple met while Whitney was filming her The Hills spin-off, The City, as Tim was a producer on the series. 

 Whitney starred on The Hills from 2006 until 2010 when she left to film The City and grow her  fashion label.

Wedding perfection: The pair tied the knot in a perfectly Pintrest wedding in Palm Springs in November 2015

Wedding perfection: The pair tied the knot in a perfectly Pintrest wedding in Palm Springs in November 2015

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