For five decades, and at the top of her game in the Sixties, Seventies and Eighties, Joan Rivers delivered her unfiltered and unforgiving comedy to millions of people. From a stand-up comedienne in the Borscht Belt of upstate New York, to a solidified name on The Tonight Show Starring Johnny Carson and The Ed Sullivan Show, Rivers' career skyrocketed, thanks in large part to those opportunities. 

Her first appearance on The Tonight Show in the early Sixties with then-host Jack Paar, wasn't the success Rivers had hoped for, and it's documented her first appearance was actually a setback in her career. That changed after Johnny Carson, long deemed her mentor, took over the show. 

Rivers certianly made a name for herself sitting next to Carson, as she would appear with him on the show nearly 100 times, and was even named the permanent guest host. 

Though Rivers' life and comedic career undoubtedly changed after appearing on Carson's show, that wasn't the only primetime program that helped launch her career. Rivers was considered a mainstay on The Ed Sullivan Show as well, making 21 appearances from her first in 1966, until the show's end in 1971. 

The same Ed Sullivan Show that famously introduced America to The Beatles and Elvis Presley, introduced Joan Rivers, by mistake. 

Before becoming a fashion critic, host of her own talk show and covering the red carpet, Rivers was a writer on The Ed Sullivan Show, writing sketches for the popular Italian mouse puppet, Topo Gigio. She landed her first appearance thanks to a similarly named guest that was scheduled to join Sullivan. 

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When teasing an upcoming guest, that was supposed to be singer Johnny Rivers, Sullivan said, ''next week, Joan Rivers!'' according to the Ed Sullivan website.

Thanks to the slip-up, Joan Rivers was immediately booked for next week's show, making her debut on May 22, 1966. 

Though she was already making a name for herself on The Tonight Show, Rivers said on a 2012 episode of The Howard Stern Show that Sullivan gave her a chance to reach the entire country, not just the East Coast and West Coast hot spots. 

''Carson gave you New York, LA, the big cities. Ed Sullivan gave you America. He put his arm around you... The midwest said 'welcome,''' Rivers said.

Sullivan introduced Rivers that night by saying, ''I was watching The Tonight Show with Johnny Carson the other night and Joan Rivers came up, she was hilarious! So here is Joan Rivers! You'll love her.'' 

People did, too. She went on to host her own show with Fox TV called The Late Show Starring Joan Rivers, which was in the same timeslot as Johnny Carson's show, a big reason for the falling out between the two.

Rivers followed that up with The Joan Rivers Show in 1989 before fashion took over, hosting E!'s Live from the Red Carpet and Fashion Police. 

Though Rivers was undeniably going to make her mark on the world, a flub from one of America's top entertainment hosts certainly helped launch her career into what it was.