If you haven't seen the viral video of Vin Diesel's emotional rendition of Rihanna's "Stay," stop reading this and watch it now. Vin posted the video on his Facebook and it boasted tens of thousands of "likes" within days. The self-proclaimed introvert wrote, "Don't be afraid to step out of your comfort zone, you don't have to be perfect ... just believe in yourself." For Valentine's Day, Vin dedicated his cover of "Stay" to longtime girlfriend Paloma Jimenez. And when their son bit down too hard on his tooth and ended up in the ER, the distraught 2-year-old asked to hear his dad's cover of Rihanna's song to help calm him down.