Guess who’s a no-show at the big Ed Markey fundraiser Tuesday night? Ed Markey.

The Massachusetts candidate for U.S. Senate landed some huge names — Joe Biden, Al Gore, Vicki Kennedy — for the high-profile party at the Kalorama home of longtime Democratic fundraiser Esther Coopersmith. Invitations went out to Washington’s A-listers to schmooze with Markey, who’s facing Republican Gabriel Gomez in the closely-watched special election later this month to fill John Kerry’s senate seat.

But now, in a major scheduling snafu, it turns out that Markey will be in Boston for the second of three live debates and miss the party here in D.C. No clear explanation why, just that the two events at the same time both ended up on Markey’s calendar. “There are two weeks remaining in the election,” campaign spokesman Andrew Zucker told us. “With such a condensed schedule, Ed’s not able to appear with the vice-president.”

This is the second planned D.C. fundraiser for Markey that went awry. In April, Robert Redford was the star attraction another Coopersmith fundraiser, but that party was postponed after Markey suspended his campaign following the Boston bombings. Last month, Redford sent out an e-mail to help raise money for Markey, but didn’t re-up to appear at this week’s D.C. event.

The longtime congressman still has an ace up his sleeve: President Obama is scheduled to campaign for him Wednesday in Massachusetts.

This story was updated at 5 p.m. to include a comment from Markey’s campaign.