Mothers and daughters don't always see eye to eye, but their bonds are deep and unshakeable. And that was the case with Debbie Reynolds and Carrie Fisher.

The two actresses died within a day of each other and are set to be buried side by side after a joint memorial tomorrow. They'll also appear on screen together one last time in HBO's upcoming documentary "Bright Lights: Starring Carrie Fisher and Debbie Reynolds."

HBO released a trailer for the doc, which is being released early due to their deaths. "Bright Lights" provides an intimate behind-the-scenes look at their lives, as Reynolds continues to perform in a Las Vegas show, while Fisher frets about her aging mother. The two women lived next door to each other in the same compound.

"My mother, she'll forget she's not 35," Fisher says as old family movies play in the trailer. "Age is horrible for all of us, but she falls from a greater height."

"Bright Lights" airs Jan. 7 on HBO.

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