Hillary Clinton and Barack Obama as running mates? Get real, says House Speaker Nancy Pelosi.

No matter who's on the top of the ticket, Pelosi told reporters Thursday on Capitol Hill that the two Democratic rivals will not team up when the dust settles.

"I think it's impossible," she said, adding that Democrats will have a "dream" ticket -- just not those two.

Asked why she felt so strongly about this, she responded: "Do you want me to go through a lifetime of political gut? Take it from me. That won't be the ticket."

The Clinton team, along with countless political speculators, have kept the idea of a joint ticket alive, but Obama said bluntly before Tuesday's Mississippi primary he does not intend to be anyone's vice president.

At this point, the two rivals, who are playing a political chess game with one another's campaign teams, would have to let bygones be bygones before embarking on a joint ticket. An Obama adviser resigned last week after calling Clinton a "monster." Clinton fundraiser Geraldine Ferraro left the campaign Wednesday after saying Obama is where is because he's black.

FOX News' Chad Pergram contributed to this report.