Two of the biggest stars of the fall TV season are Mexican thesps Fernando Colunga and Lucero.

Colunga and the single-named Lucero are the stars of “Soy tu duena,” which is the most-watched telenovela on Univision in nearly 20 years.

“Soy tu duena” is a bona fide sensation, regularly popping up among the top 10 shows in any language among adults 18-49 and top five with adults 18-34.

The telenovela is a big part of the double-digit ratings growth Univision has seen this year, in sharp contrast to the perf of the Big Four English-lingo nets. Univision’s surge in young adult viewers is a sign of the nation’s rapidly expanding Latino population, and network execs happily see it as a harbinger of growth trends to come.

Notably, “Soy tu duena” — which means “I’m Your Owner” but is translated into English for marketing and possible remake purposes as “A Woman of Steel” — is delivering more adults 18-34 viewers than any new English-language drama on the nets.

That means more young adults have tuned in to see it than shows including “Hawaii Five-0,” “Law and Order: Los Angeles,” “No Ordinary Family” and “The Event.”

But “Soy tu duena” also beats out veteran series like “The Good Wife,” “The Amazing Race,” “The Mentalist,” “Castle,” “Parenthood,” “The Biggest Loser,” “Chuck,” “Fringe” and all of the CW fare in the demo as well.

“The genre remains a force of nature,” said Univision Networks prexy Cesar Conde. “And it receives a tremendous following on so many fronts, adults and viewers of all ages. This is a wonderful example of all the things a telenovela can be.”

Since its June 1 debut, “Soy tu duena” has averaged 5.4 million total viewers, as well as 3 million in the adults 18-49 demo.

Since Sept. 20, the show has averaged 5.7 million total viewers. Last week, the telenovela — which airs at 9 p.m. most weeknights — was the second most-watched program on all of television for three nights in a row.

And with the English-language nets mostly throwing in the towel on Fridays, “Soy tu duena” is consistently the No. 1 show on the night with adults 18-34.

There’s nothing all that unique about “Soy tu duena,” which is a remake of an earlier mid-1990s telenovela.

It stars Lucero as Valentina Villalba, who is devastated after being abandoned at the altar; dashing Jose Miguel (Colunga) enters the picture to restore her broken heart.

But, of course, this is a melodrama, so there’s a love triangle — Gabriela Spanic plays the villain who’s also in love with Jose.

Lucero and Colunga are a wildly popular duo, having previously starred together in “Manana es para siempre” (Tomorrow Is Forever) and “Alborada.”

“These are arguably three of the biggest novela stars in Spanish media,” Conde said.

Thanks in large part to “Soy tu duena,” Univision is up a whopping 10.4% with viewers and 15% among adults 18-49 vs. this time last year.

And the network pulled off a major coup in September by beating all broadcasters and winning an entire week among adults 18-49 for the first time.

“That was a big milestone,” Conde said. “We continue to be the No. 5 network overall in this country. But the gap between No. 4 and No. 5 is beginning to shrink. And as for that younger demo, adults 18-34, that’s where you see a preview of what the overall audience is going to look like in three to five years. That’s a good sign for us.”

Conde said Univision is also finally getting more respect from Madison Avenue — and he suspects the 2010 census result, due at the end of the year, is a factor.

“Many heads of companies know the results of the 2010 census are coming, and they don’t want to wake up in the middle of 2011 and look at this demo explosion without a strategy for the Hispanic community,” Conde said. “Corporate America is increasingly awakening to the reality that if they want to have sustainable growth in their businesses, they have to invest in Hispanic media today.”

Given the population trends, Conde has a five-year goal that he believes is realistic: becoming the No. 1 network in the U.S. among young adults, regardless of language.

Fueling that optimism is Univision’s recent pact with Mexico’s Televisa, which is behind much of Univision’s top-rated fare. (NBC Universal-owned rival Telemundo is a distant second among Spanish nets.)

Years of animosity between Univision and Televisa, including a lawsuit that was settled last year, left plenty of uncertainty over the future of Televisa fare on Univision after their license deal expires in 2017.

But in October, Televisa took a minority stake in Univision, spending $1.2 billion to help recapitalize the channel.

“In this new partnership both goals are completely aligned,” Conde said. “We’re now a bigger force to be reckoned with.”

Deal not only extended Univision’s programming pact for Televisa fare through 2025 but also gave Univision the U.S. digital rights for the first time.

Under the previous deal, Univision hasn’t been able to stream “Soy tu duena” on its website — a glaring issue for the network.

“You will begin to see us move more aggressively in the new-media arena and offer more diverse new-media services for the Hispanic community,” Conde said. “In a new agreement, we’d be able to bring ‘Soy tu duena’ across all platforms.'”

Conde said he’ll also continue to use Televisa — which airs series around three months before the U.S. — as a testing ground for Univision.

“To have some type of lens into the performance of the programming we’re getting from Mexico, utilizing that market as our focus group, allows us to make some smart decisions,” he said.

Meanwhile, “Soy tu duena,” like all telenovelas, had an expiration date from the start; there are some 145 episodes. But rather than dwell on the fact that his hit show will soon end, Conde said he believed the knowledge that there will be closure is what helps sell the telenovela format to viewers.

One reason for the appeal “of this genre is that it has a beginning and an end,” he said.

“And if you have strong programming, it airs Monday through Friday, every night building on that success.”

Conde said he’s still assessing how to replace “Soy tu duena” once it concludes its run this month.

“We’ve got a few potential novelas being evaluated,” he said.

Spoiler alert: In the end, Valentina and Jose Miguel get married and ride off into the sunset.