ONE Championship CEO and chairman Chatri Sityodtong confirmed there have been discussions with the UFC and Bellator over Ben Askren fighting either Georges St-Pierre or Rory MacDonald.

Askren (18-0-1) called time on his career when he successfully defended his ONE welterweight title against Aoki in the main event at ONE: Immortal Pursuit in November.

Having planned his final fight in advance, the Wisconsin native claimed he would only come out of retirement to prove he was the number one welterweight in the world.

While a fight with UFC welterweight champion Tyron Woodley is out of the question as they grew up together and are teammates, Askren called for a fight with St-Pierre (26-2), regarded as the best 170-pounder of all time, while Bellator welterweight champion MacDonald (20-4) also seems to be an option after the two squared off on social media.

Sityodtong revealed ONE Vice President of Operations Matt Hume spoke with both promotions regarding a crossover fight but as of now, there is no update on whether it could happen.

"Yeah, I have an open invitation to do world champion vs world champion fights, ONE Championship vs. UFC any day," Sityodtong told International Business Times. "I know Matt Hume has talked to [UFC president] Dana White about Ben Askren fighting in the UFC against GSP [Georges St-Pierre]. ... I know Matt Hume has talked to [Bellator president] Scott Coker as well and I’ve also spoken to Scott Coker about a potential world champion vs. world champion. Let's see."

A fight against MacDonald, however, seems less likely as Coker recently revealed he would prefer for Askren to do more than one fight if the All-American were to fight the Bellator 170-pound king.

"Ben, I don’t really think wants to fight," Coker said last month. "I think he wants to fight one more fight and be done with it. That’s what I understand.”

Sityodtong was speaking at a press conference Monday to promote the organization's ONE: Unstoppable Dreams event that takes place Friday.

The card is stacked with American-Singaporean and Hawaii resident Angela Lee (8-0) defending her ONE women's atomweight championship in a rematch against Mei Yamaguchi (17-10-1) in the main event, with their first clash regarded as one of the best women's MMA fights of all time.

Lee's brother Christian (9-1) is also fighting on the card as he looks to avenge his only loss to ONE featherweight champion Martin Nguyen (10-2) and in turn, become the first sibling champions in MMA.

Angela Lee and Mei Yamaguchi Angela Lee (L) and Mei Yamaguchi (R) will headline the ONE: Unstoppable Dreams event on May 18. Photo: ONE Championship

Sityodtong was also promoting the official launch of ONE's mobile app that released just over a week earlier. Available to users around the world, MMA fans will be able to access ONE's entire video library as well as live events for free in an unprecedented move by the Singapore-based promotion.

He stated ONE Championship planned the release of the app to go alongside a big Singapore card to get even more exposure.

"I mean that's part of the plan, we were building a very big card because we know we were launching the mobile app so it was actually timed," Sityodtong said during the press conference. "We want millions and actually, billions of fans to see the beautiful work of Angela Lee, Mei Yamaguchi, Martin Nguyen, Christian Lee… These are the world’s greatest martial artists bar none."

"I wanted the whole world to be able to enjoy it and it’s no accident, we have Shinya Aoki, Eduard Folayang, Amir Khan – literally the biggest names and rising stars across a variety of mixed martial arts. ... It’s going to be super exciting, I genuinely think all these fights will end first or second round, maybe third round, all of them are going to end decisively."

A potential St-Pierre vs. Askren or MacDonald vs. Askren fight would certainly generate even more interest and should it happen, will be available to watch for free.