Monaghan, who plays a heroin addict in the hit TV series, admits his love of the 1960s band has led him astray.
He says, "I came to understand that The Beatles grew a lot and understood a lot about themselves through taking certain drugs.
"There's something very rewarding and sobering about getting involved with certain hallucinogens that strip away any sense of ego."
But Monaghan knows his limits. Unlike his Lost character, the actor views heroin as "the ultimate nightmare. You don't hear many happy heroin stories."