Los Angeles: Singer Celine Dion says she calls her twins with different names to make them respond to her. The 48-year-old shared that her youngest twins -- five-year-old Nelson and Eddy -- do everything together, but occasionally they are unresponsive, reports femalefirst.co.uk. "They are like two pieces of a puzzle, so connected that I sometimes struggle to break into their little world. I have even changed their names so they'll react,” Paris Match magazine quoted Dion as saying. "The other day Nelson didn't answer after three calls so I called 'Robert!' and he finally came. Eddy, very fearful, sends him to see about anything that scares him,” she added. Dion, who also has a 15-year-old son René-Charles with her late husband René Angélil, who passed away in January aged 73, says her twins' "worst punishment" is if they are separated from each other.