The 65-year-old former Tonight Show host was back on top form as he took over part of Fallon's famed monologue piece, after the accident-prone TV star faked an injury.
Quick as a flash, Leno was there with the jokes, poking fun at the 2016 presidential race and taking a dig at the Kardashians while he was at it.
"After that last debate, Marco Rubio is being called the best communicator in the Republican party, which is kind of like being the smartest Kardashian," the former presenter quipped.
The talk show legend then fired off jokes about President Barack Obama and the economy, after which Fallon, 41, returned to the stage and dropped in a few of his own one-liners.
"The economy is so bad in California, in Beverly Hills parents are being forced to raise their own children. That never happens!" Leno joked with his pal.
Leno handed over the reins of The Tonight Show to Fallon back in February of last year. His new show, Jay Leno's Garage, debuts tonight, Wednesday, Oct. 7, at 10:00 p.m. on CNBC.
Watch the entire monologue above and tell Us, was it good to have Leno back, or do you prefer Fallon?
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