According to Jimmy Fallon and Ethan Hawke, it's "scientifically proven" that singing lullabies in the voice of Bob Dylan helps put kids to sleep.

When the Boyhood actor appeared on last night's (March 31) The Tonight Show Starring Jimmy Fallon, he busted out his guitar along with his best Dylan impersonation, demonstrating for Fallon how he gets his young children to sleep.

Fallon, also a father, had a guitar handy himself. "We're like the Smothers Brothers," Fallon quipped as the pair launched into a rendition of "Rockabye Baby" set to a medley of Dylan lyrics. Hawke told Fallon that the technique works like a charm, and that on doing it his kids are always "out like a light."

"If my daughters are awake right now," Fallon spoke into the camera, "Winnie ... please go to sleep."

Hawke and Fallon may not have topped the vintage Saturday Night Live skit that spoofed Dylan and fellow veteran troubadour Tom Petty slurring their words so badly they needed subtitles, but the bit did elicit laughs from the Tonight Show audience.