Pete Townshend's iconic guitar-smashing routine may have only been limited to small London clubs if it hadn't been for two men who stumbled upon him and his band mates in the early '60s.

As seen in this exclusive trailer for the documentary Lambert & Stamp, two aspiring filmmakers helped transform that unknown rock outfit into the sonic powerhouse The Who. Chris Stamp and Kit Lambert simply wanted to make an underground movie about musicians when they found original members Roger Daltrey, Townsend, and John Entwistle. The two eventually scrapped everything to manage the group of peculiar musicians to superstardom.

Featuring interviews with Daltrey and Townsend, Lambert & Stamp opens in New York and Los Angeles April 3, later expanding in select theaters across the country.