Conor McGregor and Nate Diaz faced off in a pair of thrilling welterweight bouts in 2016, but their third meeting is destined to take place in a lighter division if McGregor has anything to say about it.

The UFC (and now boxing) superstar told BBC News (h/t to BJPenn.com) that should he return to the Octagon and face Diaz in a trilogy bout, it would have to be at lightweight, the division that McGregor currently rules over.

“I’m the 155-pound champion, I faced him at 170, he beat me, then I rematched him at 170, I beat him. Now I’m the 155-pound world champion. If he wants that fight, he must come down,” McGregor said. “That’s a fair trade. I didn’t ask for the rematch at a lower weight, I asked for the rematch at the exact same weight. I thought that was a fair play move on my half and then I came in and I won. So now I won that, then I won the 155-pound title after that. If he wants to fight, he’s got to make that 155-pound limit.”

Before winning the lightweight title from Eddie Alvarez last November, McGregor jumped up two weight classes to meet Nate Diaz in a 170-lb bout at UFC 196. That situation manifested itself when McGregor’s original opponent, then-lightweight champion Rafael dos Anjos, was removed from that card with an injury.

The fight with Diaz was booked to take place at welterweight due to Diaz accepting the booking on short notice. It ended in a stunning upset when Diaz defeated McGregor by second-round submission.

Diaz has spent most of his 24-fight UFC career at lightweight and previously fought for that division’s championship against Benson Henderson back in 2012, a bout that he lost by unanimous decision.

In a press conference prior to their rematch at UFC 202 (where McGregor would avenge his lone Octagon setback with a majority decision nod over Diaz), McGregor stated that it was his preference that they fight at welterweight again due to him wanting to “put everything to rest.”

Following his 10th-round TKO loss to Floyd Mayweather in his professional boxing debut this past Saturday, McGregor said he is open to boxing again in the future or returning to the UFC.