Watch My Best Friend's Girl for Free: How to Stream the Movie Online at 123Movies. . Lovestruck Dustin is dating Alexis, his ideal girlfriend, but when she dumps him for coming on too strong, Dustin takes drastic measures to win her back. He asks his best friend Tank to take her on the worst rebound date imaginable - his side job - so that she will come running back to him, and Tank reluctantly agrees. However, Alexis is more than a match for Tank's shock tactics and he begins to really fall for her, leaving him torn between loyalty to Dustin and his growing attraction toward Alexis.