The Ghost actress, 59, shared a throwback photo Tuesday of her and Willis, 67, at the Cannes Film Festival premiere of his film The Fifth Element.
"From the Cannes archives, circa 1997," Moore captioned the snap.
In the picture, Moore is dressed in a fitted black gown with a patterned black and red coat. She completed the look with a matching red clutch, statement necklace and chandelier earrings. Willis looked dapper in a classic tux as he posed for photos with his then wife.
Emma Heming Willis — who married the Die Hard actor in March 2009 — responded in the comments section, writing, "All the feels ❤️ beautiful."
This year's Cannes Film Festival started Tuesday and will run through May 28.
In March, the Willis family revealed on social media that the Golden Globe winner would be "stepping away" from his acting career.
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"To Bruce's amazing supporters, as a family we wanted to share that our beloved Bruce has been experiencing some health issues and has recently been diagnosed with aphasia, which is impacting his cognitive abilities," they wrote.
"As a result of this and with much consideration Bruce is stepping away from the career that has meant so much to him," they added.
"Happy birthday, Bruce! Thankful for our blended family 🤍," Moore captioned a photo of the duo smiling in a kitchen.