Vaishnava Samhita. Ganga Yamuna Charitam. Vol II Book VI Chp 4 Shlokas 12 - 14

आदाय गङ्गायमुने संप्राप्य स्वनिकेतनम् 
वर्धयामास सप्रेम पुत्रीभावेन स द्विजः  ||
स चापि कृपणो विप्रो नाट्यशास्त्रविशारदः 
शिक्ष्यन्नाट्यकलया मुदमाप सबान्धवः  || 
अचिरेणैव कालेन संप्राप्तनवयौवने
सुन्दर्यौ ते सहोदर्यौ नटनज्ञे बभूवतुः     ||

That brahmana took Ganga and Yamuna home. He brought them up fondly as his own daughters. That poor brahmana was an expert in Natya Shastra. Hence he taught those children the art of dancing and derived pleasure out of it. Within a short time those two sisters attained adolescence, grew very beautiful and became proficient in dancing.