Oprah Winfrey may be the queen of daytime TV, but she doesn't seem to have the same impact on the White House vote.

A Gallup Poll out Wednesday reveals that the talk show host's support of Barack Obama for the presidency in 2008 doesn't move 81 percent of people surveyed.

The latest poll showed that 8 percent of those surveyed said they are more inclined to back Obama because of Oprah's endorsement while 10 percent are less likely to vote for him because of her support.

Those numbers track pretty closely with a FOX News-Opinion Dynamics poll last month that showed 13 percent of respondents saying Oprah's endorsement makes them more likely to vote for Obama. In that poll, however, nearly three times as many people — 30 percent — said Oprah's backing makes them less likely to vote for him

The FOX News-Opinion Dynamics poll also found that 8 percent of people said they voted a certain way because of a celebrity endorsement. Though 49 percent of those polled said it’s appropriate for people to use their celebrity to encourage people to vote Almost as many — 45 percent — disagree.

According to the Gallup Poll, 37 percent said endorsements from prominent Americans are a "very" or "somewhat" important factor in helping them decide on a candidate. Sixty-one percent said endorsements are of little or no importance to them.

Will Winfrey’s endorsement make a difference? It could. First, the billionaire celebrity is well liked. The poll finds that 68 percent of Americans have a favorable opinion of her – that’s 17 points higher than Obama (51 percent favorable). And it isn’t just Democrats that have a positive opinion of Winfrey; her favorable rating is 75 percent among Democrats, 61 percent for Republicans and 65 percent for independents.

Overall, Oprah's favorability rating has dropped eight points to to 66 percent since the polling company's July survey, and her unfavorability has risen by 9 points to 26 percent. The drop appears to come most from people over age 50, 61 percent of whom say they still have a favorable opinion, but fewer than the 72 to 75 percent who favored her in prior polls.

Republicans' opinion of Oprah also dropped to 59 percent in the current poll compared to another poll taken in January that had a 69 percent favorability rating. Democrats have also lowered their opinions from 78 percent favorability before to 71 percent now. It's not clear whether the drop relates to her endorsement.

Click here for the Gallup Poll results.

Obama's support as the Democratic nominee hasn't moved much through the course of the year, but has dipped to one of its lowest points in the most recent Gallup update, from a high of 24 percent to 21 percent now. That's within the three-point statistical margin of error, but puts him 29 points behind frontrunner Hillary Clinton.

The Gallup survey was conducted through telephone interviews with 1,009 national adults, aged 18 and older over Oct. 12-14. The FOX News-Opinion Dynamics national telephone poll of 900 registered voters was taken from Sept. 11 to Sept. 12, and had a 3-point error margin.