Get A Room! Betty White & Bradley Cooper Make Out, Justin Timberlake & Jimmy Fallon Duet On SNL's Star-Studded 40th Anniversary Special

Can you believe it's been 40 years? Four decades after the NBC sketchy comedy show's 1975 premiere, current and former cast members, hosts, and big-name guest stars celebrated the series' anniversary on Sunday night.

Jimmy Fallon and Justin Timberlake kicked off the night with a musical opening monologue paying homage to the greatest SNL skits. With cameos from cast favorites Rachel Dratch (as Debbie Downer) and Molly Shannon (as Catholic school girl Mary Katherine Gallagher), the pals touched on infamous sketches including Alec Baldwin's Schweddy Balls, Christopher Walken and Will Ferrell's "more cowbell," and Timberlake's own "D*ck in a Box."

Watch out, Suki Waterhouse. Bradley Cooper was caught locking lips with a new, much older, woman— Betty White! The American Sniper actor, 40, kissed the 93-year-old TV veteran, and 2010 SNL host, during west coast soap parody "The Californians", which also featured Taylor Swift, Kerry Washington, and the skit's original star Kristin Wiig.

Girl power! Amy Poehler, Tina Fey and Jane Curtin resumed their roles as "Weekend Update" anchorwomen. Three A-listers stepped in to do their best imitations of SNL's most beloved characters. Emma Stone played the late Gilda Radner's brash reporter Roseanne Rosannadanna, Melissa McCarthy sweat it out as the late Chris Farley's wacky motivational speaker Matt Foley, and Edward Norton giggled as Bill Hader's man-about-town Stefon.

Woah, Miley can sing! Clad in a demure white pantsuit, Cyrus belted out a cover of Paul Simon's "50 Ways to Leave Your Lover." Simon himself later performed during the three hour broadcast.

Party time! Excellent! Mike Myers and Dana Carvey reunited for their beloved "Wayne's World" skit. The small-town TV hosts skewered performer Kanye West, begging the stage-storming star to stay seated. "Kanye sit down. There's a line of demarcation,' Myers, as Wayne, explained. "And social cues are such that you must stay where you are." Of course Kim Kardashian hung out with her hubby backstage.