The star took to Twitter to post a heartfelt statement and express her condolences to the family after their loss.
“My heart goes out to anyone who was lucky enough to know Alexis,” the 52-year-old wrote. “We will love and miss you forever.”
Cox was married to the late star’s brother David Arquette for 14 years.
He also broke his silence over his sister’s death with a statement on social media.
“Thank you all for your love and kind words about Alexis,” he wrote. “My hero for eternity.”
The transgender actress and activist, who starred in The Wedding Singer, died at 47.
My heart goes out to anyone who was lucky enough to know Alexis.
We will love and miss you forever.
— Courteney Cox (@CourteneyCox) September 11, 2016
Her brother Richmond Arquette confirmed the sad news on Facebook on Sunday morning.
"Our brother Robert, who became our brother Alexis, who became our sister Alexis, who became our brother Alexis, passed this morning September 11, at 12:32 am," Richmond, 53, wrote. "He was surrounded by all of his brothers and sisters, one of his nieces and several other loved ones. We were playing music for him and he passed during David Bowie's 'Starman.' As per his wishes, we cheered at the moment that he transitioned to another dimension."
Her cause of death has not been specified.
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