"No comment," Stone's publicist told UsMagazine.com when asked if the couple had ended their romance.
Stone, 54, and Mica, 27, have been dating for about eight months.
Stone is best known for her work in the film "Basic Instinct." She has been divorced twice and has three sons.
Newt Gingrich fires back at Mandela backlash
N.J. man wakes up from 10-hour sleep with knife in back