Lennon and Maisy might be the most famous actresses to have never appeared in a film or on a TV show. The Stella sisters were YouTube sensations before they debuted as Maddie and Daphne Conrad (daughters of Rayna James and Teddy Conrad) on 'Nashville.' They proved during season one of the show and on the soundtrack to the ABC drama's first season that they were cast for much more than their adorable smiles.

In May, the two sisters from Canada blew up on YouTube with a version of 'Call Your Girlfriend' by Robyn. Two days after they uploaded it, they were on their way to New York to appear on 'Good Morning America.' That first clip has over 11 million views currently, and seven other uploads of pop covers have tallied over 500,000 views. Most importantly, the press helped them get visas to work in America -- something they needed after being cast by ABC.

The two girls, ages 13 and 8, are the daughters of country music duo the Stellas. Together, the family picked up and headed to Nashville in 2009 so Marylynne and Brad could be a part of the second season of 'Can You Duet?' on CMT. They finished fourth, released an album and remained in Music City. Early videos of the girls singing were meant mostly to keep friends and family back home in Ontario close.

Eight-year-old Maisy says she's the one who landed the audition for 'Nashville.' “I auditioned and they didn’t even know I had a sister,” she told the Star in Toronto last fall. “I sang for them and they looked me up on YouTube, and they saw I had a sister and they asked, ‘How soon can Lennon get here?’"

In real life, the girls are as close as they seem on the computer. Lennon says they have a friend and fan in actress Connie Britton, who plays their mother on television. “We love her so much. She is so sweet," the older sister reveals. "She just gives you such a good vibe and she’s helped us so much."

With a Grand Ole Opry appearance lined up for Dec. 15 and a featured slot on the 'Music From Nashville' soundtrack, these girls won't be unknown in the entertainment industry for long, if it's even fair to call them that any longer. Check out the video that made them famous and scored them visas to work in the U.S. below.

Watch Lennon and Maisy Sing 'Call Your Girlfriend'