Be honest with the interviewer. Merely share if you have any relatives who work for Aldi as well as what store or office location for which they work. If you have any close friends who work for the company, be sure to mention this as well! Finally, tell the interviewer that these people really enjoy working at Aldi and have only told you wonderful things about the company.
"My best friend works at this location and is the one who told me about the opening at Aldi, and that I should apply. He has always said excellent things about working here which makes me feel great."