During Season 9 of The Real Housewives of Beverly Hills, Brandi Glanville returned just long enough to check in with Denise Richards.

Brandi has returned for Season 10, but she just hinted that things with Denise have gone sharply downhill.

In the wee hours of the morning of Monday, December 29, Brandi Glanville took to Twitter.

"I just got 'Denised,'" she tweeted vaguely.

In short order, she had more to say.

"Seriously b--ch????" Brandi wrote 11 minutes later. "You wanna play?!"

Fans were astounded to see that Brandi and Denise appear to be at odds.

"You guys were such good friends last season," one reply pointed out. "Wtf happened."

Brandi had a bit of a cameo on Season 9, dining with Denise and showing off their friendship.

"Trying desperately to promote the new season without LVP?" another tweet accused.

Other fans just wanted clarification.

"As in what Denise did to poor Heather Locklear, kind of Denised?" one asked. "Or just stoned and lots of Tequilla Denised?"

The fan argued: "There’s a lot of possibilities here, Brandi!"

Notably, Denise Richards was accused of getting too close to Heather Locklear's erstwhile husband, ending their marriage.

Whatever the source of their friction, Brandi appears to be heading into the New Year in a fighting spirit.

"Going into 2020 like..." Brandi tweeted, including a gif of herself.

Within the gif, she is saying: "Bring it, b--ch!"

That may or may not be linked to her apparent quarrel with Denise.

Brandi also posted a surprising, if deeply vague, tweet.

"1 - blackmail is illegal," she correctly asserted in the tweet.

Brandi continued: "2 - I have no skeletons in my closet (they’re all on the internet)."

“3 - slut shaming is soooooo last year," she concluded. That's also right on the money.

Earlier in December, Brandi spoke vaguely about an unidentified Housewife who was, in her opinion, acting fake AF.

"She’s faking it and she has some skeletons in the closet and guess what? They’re out. I brought ’em out,” Brandi boasted.

“I’m not a liar," she asserted. "Do I sometimes defend myself too much? Yes, but it’s a reaction."

"I love hard and I fight hard," Brandi characterized.

Could Denise Richards be the allegedly "fake" Housewife to whom Brandi was referring?

Possibly, and she does know Denise well enough to call her out if she's being a huge phony.

There's also the repetition of the "skeletons in the closet" language, though that could just be Brandi being Brandi.

But we should remember that it's very possible for a Housewife to have issues with two frenemies at the same time.

Brandi's little guest appearance on Season 9 was in the name of her friendship with Denise.

Apparently that and Brandi's penchant for drama were enough to get her invited back for Season 10.

She was spotted in early November at Kyle Richards' event, which had fans buzzing about her comeback.

If she feuds with Denise, it may actually help her chances of returning to the show. Bravo wants stars who bring the drama.

View Slideshow: Kyle Richards Tweets 29 Times, GOES OFF on Real Housewives Drama