Lisa Vanderpump may have a rough night coming up on “Dancing With the Stars.”

The “Real Housewives of Beverly Hills” star “blacked out” and fainted during a recent “DWTS” rehearsal and is still recovering.

Vanderpump wrote about the incident in her blog on People.com. She said she passed out while practicing the cha cha with partner Gleb Savchenko.

“I was in shock when I woke up. I fainted only once before in my life. The doctor found that I had a viral infection with fever and swollen glands… I ended up with low blood pressure and a rapid heart rate, which is why I fainted,” she wrote.

Vanderpump added that she is still "fighting off the bug."

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“…But I am staying in the game as long as they say I can,” she assured her fans. “And I will give it my best!”

Vanderpump and Savchenko have not fared too well thus far on the ABC competition series. The pair was close to elimination last week, but singer Wynonna Judd was sent packing instead of Vanderpump.

“Dancing With the Stars” airs Monday at 8 p.m. ET and Tuesday at 9 p.m. ET on ABC.