Lacey Chabert has announced that her older sister Wendy has died.

On Tuesday, the Mean Girls star posted a tribute to the 46-year-old mother of two, sharing a school photo from 1994. A cause of death was not disclosed, but the actress indicated that it was unexpected.

"My beautiful sister, Wendy," the 39-year-old wrote beneath the headshot. "Our hearts are shattered into a million pieces that I don't know how we will ever put back together again now that you're gone."

She continued, "We love and adore you more than we can ever say and we will continue to forever and ever and ever. The shocking loss has left us so broken hearted. Our lives will never be the same without my dear sister, but we cling to the promises of Jesus that we will be together again in eternity. Please keep our family, especially her two boys, in your hearts and prayers. Thank you so much."

Several stars shared their well wishes with the actress in the comments, with Tamera Mowry writing, "Oh dear Lacey! I'm so so sorry!!!!!!! Praying for you, Wendy's family and your family!"

Candace Cameron Bure shared her condolences, commenting, "Lacy, we are praying for you, your family and Wendy's family. We love you, always here for you my sweet sweet friend."

In August, the star shared a throwback photo of the two and their sister Crissy for National Sisters Day, captioning the photo, "Couldn't let #nationalsistersday pass without saying how much I love my two sisters. They are the best big sisters ever and I thank God for them every day. Love you Wendy and Crissy."