"These past few days I’ve been thinking about Britney and everything she is going through," the "Beautiful" singer tweeted alongside a throwback photo of her and Spears. "It is unacceptable that any woman, or human, wanting to be in control of their own destiny might not be allowed to live life as they wish."
"To be silenced, ignored, bullied or denied support by those 'close' to you is the most depleting, devastating and demeaning thing imaginable," Aguilera continued. "The harmful mental and emotional damage this can take on a human spirit is nothing to be taken lightly.
"Every woman must have the right to her own body, her own reproductive system, her own privacy, her own space, her own healing and her own happiness. While I am not behind the closed doors of this very layered & personal yet public conversation — all I can do is share from my heart on what I’ve heard, read and seen in the media."
According to the 40-year-old, Spears' "conviction and desperation of this plea for freedom leads me to believe that this person I once knew has been living without compassion or decency from those in control."
"To a woman who has worked under conditions and pressure unimaginable to most, I promise you she deserves all of the freedom possible to live her happiest life. My heart goes out to Britney. She deserves all the TRUE love and support in the world," Aguilera concluded.
Spears spoke in court on Wednesday, June 23, and said that she wanted to end her conservatorship without the need to be evaluated. The "Toxic" singer also alleged that the conservatorship was "abusive."
"I just want my life back," Spears said. "It's been 13 years, and it's been enough. I want to be able to be heard. I've kept this in for so long — it's not good for my heart."
The mom-of-two alleged that under the conservatorship, she has been subject to multiple psych evaluations and medications. Spears claimed that she was forced to do her Vegas residency after telling her management she didn't want to do the show, had her medication changed without her consent and was put on Lithium, which had a bad effect on her.
The pop sensation also said that she had no privacy at home and sometimes could not see her children Sean, 15, and Jayden, 14 — who she shares with ex-husband Kevin Federline — or boyfriend Sam Asghari, with caretakers even allegedly violating her privacy and watching her get changed.
Aguilera is just one of many stars to speak out. Following Spears' testimony, her ex-boyfriend Justin Timberlake tweeted, "we should all be supporting Britney at this time" and that "what’s happening to her is just not right."
As previously reported by OK!, Spears' sister Jamie-Lynn Spears broke her silence on Monday, June 28 — and said that she has been supporting her big sister "long before there was a hashtag and I’ll support her long after."