One of the top middleweight fighters in the world is leaving the UFC for Bellator.

Gegard Mousasi announced Monday on The MMA Hour with Ariel Helwani that he has signed with Bellator. Mousasi was a free agent following his TKO victory over Chris Weidman at UFC 210 in April. MMAjunkie’s Chamatkar Sandhu was the first to report the news Monday.

“I’m looking forward to be champion there,” said Mousasi, who added he signed a six-fight deal with Bellator. “If I achieve that, I look forward to going a division up and getting the 205 belt. But first the middleweight belt. That’s my goal.”

Mousasi (42-6-2) is on a five-fight winning streak and was angling toward a UFC title shot before his departure. The Dutchman, by way of Iran, has finished four out of those five victories. Mousasi, 31, is a former Strikeforce and Dream light heavyweight champion.

He is currently ranked No. 4 among middleweights in the UFC’s official rankings, but his four-year stint with the promotion has come to an end.

Mousasi said the UFC increased its offer from its initial proposal, but likely stopped going up when execs realized he was leaning toward Bellator. Mousasi was promoted by Bellator president Scott Coker under the Strikeforce banner and said that played a factor in his decision.

“It’s not just basically the money,” Mousasi said. “Like I said, I’ve worked with Scott. When Scott promises something, he delivers. He’s an honest guy. He’s a mixed martial artist himself. He treats fighters with respect.”

Robert Whittaker beat Yoel Romero for the UFC interim middleweight title Saturday night at UFC 213. Whittaker is very likely to get the next title shot against champion Michael Bisping. Mousasi thought that was his spot and said if the UFC gave it to him it could have swayed him to come back.

“I thought I was ahead of him,” Mousasi said of Whittaker. “That’s my opinion. I respect Whittaker a lot, he’s nice guy. Congratulations for winning the belt. I think if they would have come and said, ‘You’re fighting for the interim belt,’ things would have gotten more interesting to me.”

It won’t just be about titles for Mousasi in Bellator, he said. His first objective is winning middleweight gold, but after that he said he’s interested in fighting anywhere from middleweight to heavyweight, mentioning Rory MacDonald and Ryan Bader — a pair of former UFC fighters now in Bellator — as potential opponents. Mousasi said the UFC is strict about fighters bouncing from division to division, but Bellator is more open-minded about it.

“My feeling was saying Bellator all the way from the beginning,” Mousasi said, adding he wasn’t surprised to be leaving the UFC.

The UFC’s apparel deal with Reebok also did not sit well with Mousasi, he said. That echoes the words of just about every fighter who has gone from the UFC to Bellator since the Reebok deal began in 2015. UFC fighters are not allowed to wear their own sponsors in the cage. Plus, Mousasi added, Reebok “cant even make good pants or shorts.”

“Reebok is bad for UFC and I don’t know if the new owners (WME-IMG) realize what they're doing,” Mousasi said. “This is not entertainment; it’s different than entertainment. This is fighting.”

Mousasi said the “best choice” for him in the end was Bellator, for various reasons. Mousasi feels like he would be the favorite in the sports books against either Bisping or Whittaker, which is why he believes his asking price was reasonable.

“It’s also about treatment and getting the opportunity,” Mousasi said. “On the other hand, UFC has treated me well. I have nothing bad to say about them.”