The Beatles singer/songwriter will make his fifth appearance as musical guest, almost 46 years to the day after his 1980 SNL debut. Paul McCartney, Will Ferrell and Marcello Hernandez in 'SNL' promos NBC/YouTube Trending on Billboard Even though Paul McCartney has been making music for nearly 70 years and has a legendary catalog to pull from, Will Ferrell and Marcello Hernandez make an unusual prediction for what the Beatles singer/songwriter might perform when he appears as the musical guest on Saturday Night Live this weekend. In new promos, this weekend’s host, SNL alum Ferrell, and current cast member Hernandez appear alongside McCartney, who’s promoting his upcoming 21st solo studio album The Boys of Dungeon Lane , which arrives on May 29. But it’s not a song from his new album that Ferrell and Hernandez are expecting. “Sir Paul, everyone’s wondering what songs you’re going to play on Saturday,” Hernandez says in the promos, but McCartney responds: “I won’t tell.” Ferrell has an idea: “What if we guess?…