Ronda Rousey has switched from mixed-martial arts to professional wrestling, joining WWE.

UFC star Rousey, 30, confirmed she has signed a full-time deal with WWE after making a surprise appearance during Sunday's Royal Rumble in Philadelphia.

Rousey strolled into Wells Fargo Center wearing a leather jacket owned by late WWE legend "Rowdy" Roddy Piper. 

Wearing a Piper-themed T-shirt under the jacket, Rousey stared down Raw Women's Champion Alexa Bliss, SmackDown Women's Champion Charlotte Flair, and Royal Rumble winner Asuka and teased her participation in WrestleMania 34.

"This is my life now. First priority on my timeline for the next several years. This is not a smash-and-grab; this is not a publicity stunt," Rousey told ESPN.

"When I first met with Triple H, I told him, 'There are other things I can do with my time that'll make way more money, but I won't enjoy nearly as much.'"

Rousey's last UFC bout was a TKO loss to Amanda Nunes on December 30, 2016.

However, the UFC trailblazer would not commit to saying she has retired from mixed-martial arts.

"That's what everyone seems to say. I never retired from Judo. So if that's what you guys want to think," Rousey sayd.

"I just want to devote 100 per cent of my time to wrestling right now. Whatever people want to call that, they can call it."

Asked if she could see herself going back to fight in the UFC, Rousey replied: "I wouldn't doubt myself doing anything."