A popular UFC heavyweight is calling it quits.

Soa Palelei, who gained notoriety for his charisma and philanthropy over the last two years, announced his retirement from mixed martial arts Monday, according to a statement he released via Twitter. He was not cut by the UFC, his manager Audie Attar told MMA Fighting, despite reports.

I want to take an opportunity to officially announce my retirement from the sport of Mixed Martial Arts. Thank you to the UFC, Dana White, Lorenzo Fertitta and Joe Silva for giving me a second chance to fight for the organization. I've had a great time, but feel it's time to focus on my family and other career interests. After several months of thought and discussion with my family and my team, we realize our future includes many things in MMA, but active competition in the sport is no longer one of them. This isn't goodbye, as I will still be very much involved in the sport but just not as a fighter. I want to help further MMA around the world and give my contribution to the sport. I know that I have, and will continue to contribute much to the growth of our sport outside of the Octagon. Stay tuned guys as there is still so much more to come from "The Hulk" #‎WatchThisSpace #‎MuchLove

Palelei, 38, holds a solid 4-3 record in the UFC, but has lost two of his last three fights. He is coming off a second-round knockout defeat to Antonio Silva at UFC 190 in August. Palelei (22-5), an Australia native, was very popular in his home country and was once a ranked heavyweight. He has finished 18 of his 22 victories by knockout. Palelei had one fight in the UFC back in 2007, a loss to Eddie Sanchez at UFC 79, before returning in 2013.

Earlier this month, Palelei raised thousands of dollars for sick kids at the Princess Margaret Hospital for Children in his native Western Australia. However, when he and fellow fundraiser Matt Fuller, an Australian Rules football player, attempted to set up a visit to the hospital to see the kids, Palelei was told he could not attend.

Cage fighting is illegal in Western Australia and the hospital did not want someone from the UFC meeting with the children.

"It's so disappointing," Palelei told MMA Fighting at the time. "I was kind of heartbroken when they told me. I was like, 'What? Are you serious?' I'm a big fan of boxing, but you've got 12 rounds continuously getting punched in the head. MMA, 80 percent of it is grappling and submissions. It's just crazy. I guess it's just narrow-minded people."

That didn't stop Palelei from a planned charitable marathon. He and Fuller spent 24 hours on a stationary ergo grinder exercise machine this past weekend. The two athletes raised more than $120,000 for the children at Princess Margaret Hospital, according to Yahoo! Australia.

Palelei, whose nickname is "The Hulk," said being spurned by the hospital did not deter him at all from wanting to raise money for ill children. He is also an ambassador for the Make-A-Wish foundation.

"This is what I like doing," Palelei said. ... "Our sport is nothing compared to what these kids go through all day every day."

Palelei said it is one of his life's goals to give back and that will surely be one of his top plans for his post-MMA life.