As Olivia Rodrigo prepares to pull double-duty this weekend on Saturday Night Live , she has support from a fellow musical guest. The 3x Grammy winner, who makes her hosting debut and her third performance as musical guest Saturday on the NBC sketch comedy show, revealed that Jack White left her some words of encouragement on a hidden note in her dressing room. “I love Jack White. He’s, like, my hero,” Rodrigo raved on The Tonight Show Starring Jimmy Fallon . “He’s the coolest guy ever. Wonderful person. Always stands up for what’s right.” White previously got his Five-Timers Club jacket when he served as the musical guest on the April 4 episode, alongside host Jack Black. Rodrigo said, “But I was on the phone with him the other day, I was like, ‘Oh my god, I’m gonna host SNL .’ He’s like, ‘I’m gonna leave a note in your dressing room.’ I was like, ‘Haha. Ok, funny.’ I feel like I’d maybe said that to someone too but never done it. “He sent me a text and he’s like, ‘Look up!’ Like, ‘Keep your head up.…