These celebrities may be A-listers now, but they were no names when they made their debuts as nervous stand-up comedians on The Tonight Show Starring Johnny Carson. Take a look back at how the careers of Jerry Seinfeld, Roseanne Barr, Jim Carrey and more funny folks got underway.

Roseanne Barr made her national stand-up debut on The Tonight Show in August 1985, three years before her sitcom Roseanne would premiere. But her no-holds-Barred approach to comedy was already well established, as her routine included a segment about her feelings as an overweight, disgruntled housewife.

More than three decades before he won an Emmy for FX's Baskets, Louie Anderson was a just-starting-out comedian when he appeared on The Tonight Show in 1984. Stardom would come later, but the foundation of Anderson's humor was already present, with the comedian cracking jokes about his weight and telling endearing (and hilarious) stories about his father.

Before he joined the cast of Saturday Night Live, Kevin Nealon made the first of many stand-up appearances on The Tonight Show in 1984. He later credited The Tonight Show, even more so than SNL, with cementing his comedy career, likening the debut performance to "passing the bar exam as a lawyer." Here, he's pictured during a 1995 visit to the late-night show.

Though she was later infamously banned from The Tonight Show, Joan Rivers' banter with Carson made her a household name long before she became a fixture on E! and cemented her own place in late night as the first female host of a late-night show. Her first appearance occurred in the early 1960s, while Jack Paar was still sitting behind the host's desk, but she became a regular with Carson at the helm. He acted as her mentor for decades until their infamous feud, which began in 1986 when she agreed to host a new talk show on Fox opposite The Tonight Show. Before that, Rivers was the go-to guest host in Carson's absence. Nearly 30 years after being banned from the show, Rivers returned in 2014 to be interviewed by new host Jimmy Fallon.

Jim Carrey made his first of many appearances on The Tonight Show in November 1983, a few months before the premiere of his sitcom The Duck Factory. During that debut, hedid a number of celebrity impressions, from Elvis to Miss Piggy. Despite wowing the crowd, he didn't get invited to come chat with Carson after that appearance. Here, he's pictured during a 1991 visit with guest host Jay Leno.

During Seinfeld's run from 1989 to 1998 on NBC, viewers caught a glimpse of Jerry Seinfeld's stand-up routines week after week. But the Tonight Show audience got a sneak peek of this years earlier, when Seinfeld made his debut on the late-night show in 1981. It was his first of several appearances on various iterations of the show.

Before he became known for his own sitcom, the Blue Collar Comedy Tour, and the comedy album You Might Be a Redneck If..., Jeff Foxworthy caught the eye of Carson when he made his Tonight Show debut in 1991.

Tim Allen's sitcom Home Improvement had already premiered when the comedian made his first Tonight Show appearance in November 1991. The late-night debut didn't go so well, but nevertheless, Allen got a rare invitation from Carson to sit on the couch for a chat, where he explained that he felt paralyzed by nerves. He got over them, however, and has returned to the show several times since.

Before he became host of The Tonight Show, a title he held from 1992 to 2014 with a notorious year off in between, Leno made a number of appearances on the show as a young comedic upstart. He did his first stand-up routine in 1977, and so admired his predecessor Carson that he upheld Carson's infamous ban on Joan Rivers for the entire time he hosted the program. Here, Leno is pictured during a 1979 appearance when he was interviewed by guest host David Letterman.

A former sitcom writer who was trying to break into stand-up, the late Garry Shandling performed on The Tonight Show for the first time in early 1981. Carson and the audience took a shine to Shandling, who was asked repeatedly to fill in as a guest host for Carson in subsequent years. Later, he went on to host his own (fake) talk show, The Larry Sanders Show.

The Tonight Show audience was introduced to an unknown comedienne named Ellen DeGeneres on Nov. 18, 1986, when she delivered a side-splitting routine featuring a lengthy imagined telephone conversation with God. Though it would be another eight years before her sitcom Ellen premiered, it was clear that DeGeneres was well on her way to stardom: She was the first female comic whom Carson invited over to his couch on her first appearance.

The Drew Carey Show didn't premiere until 1995, but four years earlier the comedian gave a seven-minute performance on The Tonight Show that kick-started his career -- and earned him an elusive spot on Carson's couch.

When one thinks of David Letterman's association with The Tonight Show now, a bitter feud comes to mind. But his earlier relationship with the show dates back to 1978 when he made his first appearance as a guest comedian. The audience gave him a lukewarm reception, but it set the stage for Letterman's frequent cameos as a guest host in Carson's absence (he's pictured here behind the desk in 1979 with guest Betty White), and subsequent long-running gig as host of The Late Show.

Now, he hosts his own political-themed gabfest, but nobody knew who Bill Maher was when he made his debut on The Tonight Show in August 1982. It wasn't until his fifth appearance on the show that he received the honor of being invited to sit down on Carson's couch, but even being asked back to the show at all was an achievement for Maher. "It was the baccalaureate of stand-up, a test you took early on that would decide the rest of your life. If you did well, you'd get invited back and you might be on to a career. If you didn't, it was pretty much over," Maher told Newsweek in 2012.