Former "Dancing With the Stars" contestants Alexa and Carlos PenaVega claimed on a recent episode of their "LexLos" podcast that pro dancers Witney Carson and Mark Ballas were feuding throughout Season 21 in 2015.

"At the time, Witney and Mark were not getting along at all. They refused to be in the same room together," Alexa, 38, said, per Page Six.

The couple made history that season as the first married pair to compete against one another on the show, with Alexa paired with Ballas and Carlos dancing with Carson.

The claim is striking because the married couple's entire plan for the show depended on the two pros cooperating.

"The whole point of doing the show was, 'We're going to go in, and we're going to do this together as much as possible.' And the second we go in, boom, Mark and Witney refused to be in a room together," Alexa recalled, according to Page Six.

She said the pair expected to rehearse in the same room and instead had to stay separate and "dance around whatever's going on with them." TV Shows Ace notes fans had never heard about this tension before the podcast reveal.

The podcast episode included more reflections on the 2015 season. Carlos, 37, told Page Six he and Carson, 33, "had so much fun" and that he was "there to win" — but so was Ballas, 40, whom he called "very creative" and eager to "do things outside the box, which require a lot of work."

Alexa admitted she struggled more with learning routines: "Mark would teach me something, and I'd be like, 'All right, got it'... then an hour later, I'd be like, 'I actually don't remember any of that.'"

Carlos placed fourth, while Alexa and Ballas finished sixth behind winners Bindi Irwin and Derek Hough.

TV Shows Ace reports that the claims resurfaced long-standing, unconfirmed fan rumors that Ballas and Carson had a fling years ago when both were single, before Carson married Carson McAllister in 2016 and Ballas married BC Jean in 2016. Neither rumor has ever been confirmed.

Page Six reports it reached out to representatives for Carson, Ballas and "DWTS" for comment but did not immediately hear back, so the feud claims remain one-sided accounts from two former contestants on their own podcast.

The stakes extend to the current season, where both pros returned after a decade of competing.

According to Page Six, Carson — who won Season 34 with Robert Irwin — was eliminated during "Super Bowl Night" this season alongside partner Guillermo Rodriguez, while Ballas and his partner, Maura Higgins, are still in the running for the Len Goodman Mirrorball Trophy.

TV Shows Ace notes the reveal landed amid other "DWTS" drama, including Val Chmerkovskiy's reported clash with Carrie Ann Inaba, keeping behind-the-scenes tensions in the fan conversation.