During her opening monologue on “ Saturday Night Live U.K.,” host Nicola Coughlan got a little assistance from “ SNL ” legend Jimmy Fallon, who joined the “Bridgerton” star for a chaotic studio tour and an explicit rap about her new family film “The Magic Faraway Tree.” Coughlan kicked off her monologue by poking fun at her “Bridgerton” character, saying she “played an aristocrat who came out as a messy bitch who lives for drama,” and joking that she decided to channel the “magic” of the original ’70s “SNL” by consuming a “staggering amount of cocaine.” “It’s an honor to be hosting. It sort of feels like I manifested it somehow — it’s almost like this place is like magic,” Coughlan said as Fallon appeared. “That’s because it is!” he said. Popular on Variety Fallon then shared with Coughlan the “biggest secret of ‘SNL.'” “Well, don’t tell anyone, but it’s live,” Fallon said. “It’s actually live. I mean, you can do whatever you want, you can go wherever you want. You’re the host.…