The WWE wrestler went nude to shoot the cheeky video, alongside his athletic partner who also removed all her clothes to mark the achievement.
"What up everyone, so we are finally ready to have this huge celebration – sorry it took a few days, it took a while to convince someone to do this," Nikki told the camera while pointing at her fiancé.
"I still don't think this is a good idea," said a reluctant John, dressed in a tight grey t-shirt.
"OK this is a very good idea. Why? Because we got half a million subscribers! So we are ready to give all of us to all of you," shot back Nikki, who had on a bright orange silky dressing gown.
"Not a good idea," said a clearly concerned John.
"Just shut up and take your clothes off," Nikki told him.
The two then bent down out of shot and John peeled off his shirt, revealing a seriously muscled chest and chiselled six-pack.
As Nikki turned her back to the camera, John asked: "You're actually doing this?"
"Yeah, I'm going to do this. Right? Half a million, love," said Nikki while shimmying out of her gown and getting completely naked.
The nude pair then danced around whooping, before John joked: "I think my tube's on YouTube."
But it wasn't long before the tone was lowered, by the wrestling star breaking wind.
"What the f**k? Are you kidding me? What did you eat, someone else's farts?" cried Nikki before storming off.
John was left standing naked in front of the camera, saying, "So this didn't go right", before Nikki stormed back to throw her screwed up sign at his muscly pecs.
The YouTube video has already racked up almost one million views, and responses have been overwhelmingly positive for the happy couple.
John proposed to Nikki live on Wrestlemania earlier this month, dropping to one knee and whipping out an enormous diamond ring in front of millions of viewers.
"I have been waiting so long to ask you this," John told her. "Will you marry me?"
The Total Bellas star wiped tears from her eyes after kissing her hunky beau and accepting the blingy ring from him, to the happy cheers from delighted fans.
The next day, he explained his motive behind the public proposal – and revealed he'd known he was going to ask her to marry him for a long time.
"I told the story last night before I proposed to Nicole about, she has been by my side through a lot of surgeries," he explained to the Today show in the US.
"I know when they put you under anaesthesia, you have 20 minutes when you're out of it but you can talk and you don't remember what's going on.
"They're going to put me under. Ask me whatever you want. You're going to get the answer," he said.
And when Bella had to have her own surgery on her neck 18 months ago, John made sure he was by her side before she lost consciousness.
"When they put her under, I made sure to be the last one to wheel her into the OR [operating room]. At the moment of no return, I stopped the doctors and I asked, 'Can you hear me?' 'Yes.' 'I have one question for you,'" he recalled.
"'What?' You know someday I'm going to marry you?"
