Britney Spears took to Instagram on Thursday to flaunt four different outfits as she celebrated her 40th birthday.

Her first outfit was a dress with full sleeves which she wore while posing in front of a massive Christmas tree. She also wore a Christmas tree locket around her neck.

For the second outfit, she wore a deep V-neck red dress with hanging sleeves. She kept one hand on her waist and posed for the camera. In the next outfit, she donned a multicolored dress with bell sleeves and a necktie. In the next photo, she wore a plain yellow dress, which she completed with black sandals.

"I’m not turning 40 … I’m turning 4 and if any of you haven’t HEARD … I did almost 250 shows in Las Vegas for 4 years and went out twice," she captioned the photos.

"With that said … I think I will have to put on my hot little dresses on every night for the rest of my life to break even for working for my family my whole life with only old songs permitted !!!" she added.

Spears noted she will be sharing more "classic fashion dresses" on her Instagram soon, and those dresses will be designed and worn by her.

The comments section of the post was filled with wishes and compliments. While many fans wished the pop star on her birthday that she celebrates on Dec. 2, others praised her beautiful dresses.

Spears also shared some PDA-filled moments between her and her fiancé Sam Asghari on Instagram on Wednesday as the couple went to Mexico to celebrate the singer's birthday. "Oh the precious joy today!!! Me and my fiancé are so excited to be going away," she captioned the photos.

"It's the first birthday where Britney doesn't feel like she's just withering away," a source told EOnline on Thursday. "This year, they're happy to celebrate Britney getting older because she's finally growing into her true self."

"She finally feels like she has purpose and Britney wants to celebrate that to the fullest," the source added.

The couple began their relationship in January 2017 after meeting for the first time in 2016 on the set of the music video for "Slumber Party."

Britney Spears, shown here in 2019, has indicated she would like to have another child and has plans to wed her boyfriend Sam Asghari Britney Spears, shown here in 2019, has indicated she would like to have another child and has plans to wed her boyfriend Sam Asghari Photo: AFP / VALERIE MACON