Rumer Willis in Miami for Film Fest
03/06/2012 AT 09:00 AM EST
Willis, 23, attended the premiere of The Diary of Preston Plummer, where she cut a glamorous figure in a curve-hugging dress.
"It was fun making the movie and fascinating working with Robert Loggia," she told PEOPLE of starring alongside the longtime character actor in the film. "I wasn't in many scenes with him but it was cool being around so much wit and wisdom."
It was likely a relief for Willis to focus on professional duties. The oldest daughter of Moore and Bruce Willis may have been present for the 911 call that sent her mother to the hospital back in January, and has taken an active role in keeping the family together in Moore's absence.
Rumer attended her younger sister Tallulah's 18th birthday bash last month and reportedly encouraged Moore's estranged husband, Ashton Kutcher, to visit Moore during her treatment.