Roman Reigns relinquished his WWE Universal title in an emotional speech on Monday Night Raw.
Reigns, whose real name is Joe Anoa'i, has been diagnosed with leukaemia. The 33-year-old was first diagnosed with the illness 11 years ago. It went into remission in 2008 but has now returned.
In a statement, the WWE said that Reigns will take a leave of absence while he battles the disease.
"I feel like I owe everybody and apology," Reigns told the crowd
For months, maybe even a year, I've come out here and spoken as Roman Reigns and said a lot of things. I said that I'd be here every single week, I said I'd be a fighting champion, I said I was going to be consistent and I said that I was going to be a workhorse.
That's all lies. It's a lie because the reality is my name is Joe and I've been living with leukaemia for 11 years and unfortunately it's back.
Because the leukaemia is back, I can't fulfil my role. I can't be that fighting champion and I'm going to have to relinquish the Universal Championship. I'm not going to lie, I'll take every prayer you can send my way but I'm not looking for sympathy, I'm not looking for you to feel bad for me because I have faith.
When I was 22-years-old, I was diagnosed with this and very quickly, I was able to put it in remission. I'm not going to lie, that was the hardest time of my life. I didn't have a job, I didn't have any money, I didn't have a home and I had a baby on the way. Football was done with me, but do you want to know who gave me a chance? The team that gave me a chance was the WWE.
Reigns vowed that he will return to the ring.
"I want to make one thing clear: By no means is this a retirement speech because after I'm done whupping leukaemia's ass, I'm coming back home. And when I do, it's not going to be about titles and being on top, it's about a purpose.
"I'm coming back because I want to show you all at home and my family and my children and my wife that when life throws a curveball at me, I will choke up and I will swing for the fences every single time. I will beat this and I will be back so you will see me very, very soon."