Alan Rickman's voice can stop moviegoers in their tracks, even from beyond the grave.

The Harry Potter star and theater legend, who died last month after a short battle with cancer, will still appear in the forthcoming Alice Through The Looking Glass as the voice of the animated Blue Caterpillar character. And in a new trailer that debuted yesterday (February 1), his words warn the titular character that danger looms.

"You've been gone too long, Alice," the character says in the clip above across short video bits that feature Anne Hathaway, Johnny Depp and Mia Wasikowska. "There are matters which cannot be neglected."

The movie picks up three years after 2010's Alice In Wonderland and find Alice on a mission to save the imperiled Mad Hatter, according to Entertainment WeeklyMore generally, it will speak to themes of growing up and figuring things out.

"[Alice] faces that moment that a lot of young adults do in their twenties, which is that the way you spend your time is really important of what you’re going to accomplish in your life,” producer Suzanne Todd told EW. “She has to face this decision of what she’s going to do with the rest of her life."

Listen to Rickman's voice in the video above, and be sure to see Alice Through The Looking Glass in theaters in May.

Look back at stars we've lost over the past year: