For any person to be proficient in Fine arts, particularly singing, Venus is the Significator.
In Stefanie's horoscope, Ascendant is in Poorva Shadha nakshatra , a nakshatra owned by Venus. Mars in her horoscope is the 5th lord of Creative talents. Mars in her horoscope is in her ascendant which is Sagittarius and is in Poorva Shadha nakshatra again.
Saturn, the karma karaka and the Second lord of Speech and Voice is in the 5th house of creative talent, Aries and in the Bharani Nakshatra. Again, Bharani nakshatra is owned by Venus !!!
And finally the Significator of Singing, Venus is in her 9th house in Leo and in the nakshatra of Poorva Phalguni. Poorva Phalguni is again a nakshatra owned by Venus !!!
Influence of Venus on all key planets is very much evident and responsible for her career and fame in singing.
Data Source :
https://www.astro.com/astro-databank/Stefani%2C_Gwen
Click on the above link to know more details about the singer.