She welcomed her first child on October 1st.
And Heidi Montag has been hard at work getting her post-pregnancy body back into pre-pregnancy shape.
The 31-year-old reality star announced she lost 25 lbs. since welcoming son Gunner with husband Spencer Pratt via social media on Thursday.
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Dropping: Heidi Montag has been hard at work getting her post-pregnancy body back into pre-pregnancy shape
The Hills alum cut a casual figure in a light pink top as she took to Instagram to let her fans in on her weight loss progress.
‘I lost 25lbs! Post baby body’ she captioned the shot of herself with her trademark blonde tresses swept back in a ponytail.
The former MTV starlet was hard at work returning to her former physique as she was often snapped in saucy bikini pics before her pregnancy.
![Fitness: The 31-year-old reality star announced she lost 25 lbs. since welcoming son Gunner with husband Spencer Pratt via social media on Thursday](https://i.dailymail.co.uk/i/pix/2017/12/22/07/4783610400000578-5204973-Fitness_The_31_year_old_reality_star_announced_she_lost_25_lbs_s-a-1_1513929381633.jpg)
Fitness: The 31-year-old reality star announced she lost 25 lbs. since welcoming son Gunner with husband Spencer Pratt via social media on Thursday
![Proud mama: 'I lost 25lbs! Post baby body' she captioned the shot of herself with her trademark blonde tresses swept back in a ponytail](https://i.dailymail.co.uk/i/pix/2017/12/22/07/4783747E00000578-5204973-image-m-32_1513927574327.jpg)
Proud mama: ‘I lost 25lbs! Post baby body’ she captioned the shot of herself with her trademark blonde tresses swept back in a ponytail
Meanwhile, Heidi posted a sweet snap of the young adorable family as they ushered in the holiday season.
The happy couple sweetly cradled newborn Gunner who calmly posed for pictures with his parents.
Heidi was radiant in red. The mother-of-one layered a loose, bell-sleeve dress underneath a fur-like vest.
![Adorable: The happy couple sweetly cradled newborn Gunner who calmly posed for pictures with his parents](https://i.dailymail.co.uk/i/pix/2017/12/22/07/4783727500000578-5204973-image-a-27_1513927467580.jpg)
Adorable: The happy couple sweetly cradled newborn Gunner who calmly posed for pictures with his parents
![Transformation: Heidi was very pregnant in 2017 and bikini ready in 2011](https://i.dailymail.co.uk/i/pix/2017/12/22/08/4783783A00000578-5204973-Transformation_Heidi_was_very_pregnant_in_2017_and_bikini_ready_-a-79_1513930312820.jpg)
![Transformation: Heidi was very pregnant in 2017 and bikini ready in 2011](https://i.dailymail.co.uk/i/pix/2017/12/22/08/4783783E00000578-5204973-Transformation_Heidi_was_very_pregnant_in_2017_and_bikini_ready_-a-81_1513930312897.jpg)
Transformation: Heidi was very pregnant in 2017 and bikini ready in 2011
Spencer looked handsome in a button-up, grey sweater and jeans.
Gunner was quite the handsome little man in a white button-up, red sweater, blue pants and soft reindeer slippers.
On Friday, Heidi took to social media to share a selfie of her and her family.
![Family affair:Meanwhile, Heidi also posted a sweet snap of the young adorable family as they ushered in the holiday season](https://i.dailymail.co.uk/i/pix/2017/12/22/08/4781B6D700000578-5204973-Family_affair_Meanwhile_Heidi_also_posted_a_sweet_snap_of_the_yo-a-80_1513930312855.jpg)
Family affair:Meanwhile, Heidi also posted a sweet snap of the young adorable family as they ushered in the holiday season
!['Christmas is my favorite time of year!': On Friday, Heidi took to social media to share a selfie of her and her family](https://i.dailymail.co.uk/i/pix/2017/12/09/04/4720378000000578-5161885-image-m-83_1512793041107.jpg)
‘Christmas is my favorite time of year!’: On Friday, Heidi took to social media to share a selfie of her and her family
‘Christmas is my favorite time of year! So blessed to have @gunnerpratt to share all the new traditions and memories! All I want for Christmas is my baby! Gunner looks very amused by his parents selfies,’ she wrote.
The photo was taken while the trio went out to buy their Christmas tree on Tuesday.
The duo first me as co-stars on the MTV reality drama, the Hills, in 2007 and recently celebrated their nine-year wedding anniversary.