Houston mayoral candidate Sheila Jackson Lee tells supporters to vote on wrong date

Houston mayoral candidate Rep. Sheila Jackson Lee, D-Texas, encouraged her supporters to get out and vote for the runoff election — but she gave the wrong date.

Jackson Lee, who currently serves in Congress, is looking to defeat Democrat state Senator John Whitmire in the race to replace outgoing Mayor Sylvester Turner.

The race has moved to a runoff between the two that is scheduled for Saturday, Dec. 9, and Jackson Lee released a television ad to spur her supporters to the polls.

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The congresswoman's ad highlighted her record during her political career on several issues, including abortion and gun violence.

However, Jackson Lee's ad contained a critical error: the ad said to vote "on or before December 7" — two days before the runoff election is scheduled.

According to Mediaite, the ad made it to air in Houston television markets — a major late-game hiccup by the veteran congresswoman.

The ad could hurt Jackson Lee as she fights Whitmire for the mayorship of the largest city in Texas. Voters could get confused and not know that the election date is set for two days later.

Fox News Digital reached out to Jackson Lee's campaign for comment but did not immediately receive a response.

Jackson Lee's ad stumble may spell trouble for her, but it most certainly will bring storm clouds over her staffers.

The Texas Democrat has built a reputation as one of the "meanest" members of Congress to work for, but has also become one of its most recognizable faces, having represented the same district in the House of Representatives for more than 28 years. 

Jackson Lee has long been known as one of the most difficult members of Congress to work for, and, according to a 2011 Daily Caller report that cited a number of former staff members, frequently used demeaning language and name-calling when addressing them.

"You stupid motherf---er," one former employee said Jackson Lee "constantly" called him, while another described an occasion her parents were visiting from out of town and overheard Jackson Lee call her a "stupid idiot" because of a scheduling change. "Don’t be a moron, you foolish girl," the former aide alleged Jackson Lee told her.

Another former aide alleged Jackson Lee once told them, "You don’t understand. I am a queen, and I demand to be treated like a queen."

Fox News Digital's Brandon Gillespie contributed reporting.