Junior lightweight world titleholder Vasyl Lomachenko and unified junior welterweight world champion Terence Crawford, two of the best pound-for-pound fighters in the world, will defend their crowns in August live on ESPN.

Promotional powerhouse Top Rank and the network, which have already partnered on Manny Pacquiao's welterweight title defense against Jeff Horn -- which will air on ESPN and ESPN Deportes, along with several undercard fights, beginning at 9 p.m. ET Saturday from Brisbane, Australia -- have partnered for two more major summer cards.

Lomachenko will defend his 130-pound belt against hard-charging Miguel Marriaga, a former featherweight world title challenger, on Aug. 5 at the Microsoft Theater in Los Angeles.

Two weeks later, on Aug. 19, Crawford will face fellow two-belt world titleholder Julius Indongo at Pinnacle Bank Arena in Lincoln, Nebraska, a short drive from Crawford's hometown of Omaha. Crawford-Indongo will be only the fourth fight in the four-belt era in which all four major titles will be on the line in the same fight; the winner will walk away as the undefeated, undisputed No. 1 fighter at 140 pounds.

Both fights, along with undercard action, will be televised live on ESPN and ESPN Deportes and stream live on the ESPN app beginning at 10 p.m. ET.

"ESPN is thrilled to bring these two new title fights to fans," Burke Magnus, ESPN's executive vice president of programming and scheduling, said Thursday. "There is a lot of buzz around boxing right now, and much of it centers around these two great champions -- Lomachenko and Crawford. We are excited and proud to showcase these two great events on all of our platforms."

Top Rank president Todd duBoef, who worked closely with Magnus to finalize the deal, was also excited about the exposure his two champions will get on ESPN.

"Pound for pound, no one can match the talent of Vasyl Lomachenko and Terence Crawford," duBoef said. "They drew the best ratings on premium cable this year, and now everyone will be able to see them when they defend their world titles in all-action fights in August, live on ESPN."

Lomachenko and Crawford have been a staple on HBO for the past few years, but duBoef has wanted to bring his top fighters to a wider audience than the premium cable network has available. The deal for the upcoming Lomachenko and Crawford fights has been in the works but could not be finalized until the fighters no longer had obligations to HBO, which had the right to match the ESPN offer. HBO allowed its window to match to close Thursday without making an offer.

Vasyl Lomachenko, ranked No. 4 on ESPN's pound-for-pound list, will meet Miguel Marriaga in a fight that will air live on ESPN on Aug. 5. Matt Hazlett/Getty Images

Lomachenko (8-1, 6 KOs), 29, is a two-time Olympic gold medalist from Ukraine and considered by many to be the greatest amateur boxer in history (396-1 with the loss avenged). He tied the boxing record by winning a world title in his third professional fight in 2014 when he claimed a featherweight belt. He defended his 126-pound crown three times and then moved up to 130 pounds and won another title last June in his seventh fight, setting the record for fewest fights needed to win titles in two weight classes.

Lomachenko had hoped to face former two-division titleholder Orlando Salido in a rematch of Salido's split-decision win in 2014 in Lomachenko's second pro fight. However, after much discussion, Salido ultimately rejected an offer of $720,000, and Top Rank moved on to Marriaga for Lomachenko's third title defense.

"When the financial requests were met suddenly there were other issues like a hand problem, which led to a weight problem, which led to Marriaga. Funny how that happens," Top Rank vice president Carl Moretti said. "So we moved on to trying to secure the best possible opponent at the time, and Miguel Marriaga stepped up to the plate as did [previous Lomachenko opponents] Jason Sosa and Rocky Martinez in the past."

Marriaga (25-2, 21 KOs), 30, of Colombia, lost a decision to Nicholas "Axe Man" Walters in a vacant featherweight title bout in 2015, when Walters was overweight and stripped of the belt, leaving it only on the line for Marriaga. Marriaga won his next five fights and then challenged featherweight titlist Oscar Valdez on April 22, and although he lost a decision, he gave Valdez hell in a brutal slugfest.

Lomachenko will be a big favorite, but he would be one against anybody in the world in his weight division, Moretti said.

"If you put Marriaga, Salido and Sosa in a round-robin, I think they're all excellent fights, and who knows who would win," Moretti said. "Obviously, Lomachenko is at a different level, but in the ring we know what Marriaga brings -- heart, determination, a big right hand, size and no intimidation."

The co-feature will pit former two-time lightweight title challenger Raymundo Beltran (33-7-1, 21 KOs), 35, a Mexico native fighting out of Phoenix, and former interim junior lightweight titlist Bryan Vasquez (35-2, 19 KOs), 29, of Costa Rica, in a 10-round lightweight fight.

Crawford (31-0, 22 KOs), 29, who was the 2014 consensus fighter of the year when he was lightweight champion, has made five junior welterweight title defenses, including unifying two belts by lopsided decision against Viktor Postol last July and stopping former Olympic gold medalist Felix Diaz in the 10th round on May 20.

Now he will attempt to unify the four belts against Indongo (22-0, 11 KOs), 34, of Namibia. Indongo will be making his second defense and trying to do the same.

Indongo traveled to Moscow and spectacularly knocked out hometown hero Eduard Troyanovsky in the first round in December to win one title. Then he traveled to Ricky Burns' hometown of Glasgow, Scotland, and easily outpointed him to unify two belts on April 15. Now he is going to Crawford's home area looking to add the other two belts to his collection.

"The fact that we were able to secure this for all four belts is truly history-making," Moretti said. "Both sides deserve credit in their willingness to do this. I'd like to thank [Indongo co-promoters] Eddie Hearn [of Matchroom Boxing] and Nestor Tobias for truly wanting to make this fight.

"Indongo went to Russia to knock out Troyanovsky, and then he went to Scotland and beat Burns. Does he actually have the audacity to come to Nebraska and beat Crawford for the other two titles? We'll find out Aug. 19."

Only three times previously have all four major belts -- the WBC, WBA, IBF and WBO -- been at stake in the same fight: once in 2004, when Bernard Hopkins put his three belts up against Oscar De La Hoya's one and knocked him out to unify the middleweight division, and twice in 2005, when Hopkins retained them by outpointing Howard Eastman and then lost them by decision in his first fight with Jermain Taylor.

It wasn't easy to get done for Crawford-Indongo, because Indongo had an IBF mandatory defense due against Sergey Lipinets and Lipinets' team fought hard to prevent Crawford-Indongo. However, the IBF ultimately approved an exception and allowed its title to be on the line.

"The willingness and cooperation from all four organizations certainly reflects their concern and desire to do what's right for the sport," Moretti said.

In the Crawford-Indongo co-feature, light heavyweight contender Oleksandr Gvozdyk (13-0, 11 KOs), 30, a 2012 Olympic bronze medalist from Ukraine, will face an opponent to be determined in a 10-rounder.

The undercard will also feature several name fighters against opponents to be determined: newly signed Top Rank heavyweight Bryant Jennings (19-2, 10 KOs), 32, of Philadelphia, a former title challenger returning from a 20-month layoff; British heavyweight contender Dillian Whyte, (20-1, 15 KOs), 29, who is coming off a split-decision win against Dereck Chisora in a wild 2016 fight of the year contender in December; 2016 U.S. Olympic silver medalist Shakur Stevenson (2-0, 1 KO), 20, of Newark, New Jersey; and Walters (26-1, 21 KOs), 31, of Jamaica, fighting for the first time since Lomachenko made him quit in the seventh round of a one-sided junior lightweight world title fight in November.