New York (CNN) -- Embattled lawmaker Charlie Rangel, who is embroiled in an ethics investigation, celebrates his 80th birthday Wednesday -- but the event may lack much of its promised luster.
The "birthday gala" is being held at The Plaza Hotel in New York City, a day after the 20-term congressman apologized on the House floor for causing any embarrassment by violating chamber rules.
In a video montage accompanying an invitation sent out to supporters late last month, former President Bill Clinton delivered his birthday wishes.
Clinton is not attending the party, saying he will be in Arkansas on Wednesday.
The video also touted a performance by the queen of soul, Aretha Franklin.
But the legendary soul singer is nursing fractured ribs and has had to reschedule two free concerts.
"I will really miss that nice slice of cake from Congressman Charlie Rangel's birthday party and singing 'Happy Birthday' to him," Franklin, 68, said in a statement.
A number of other high-profile New York Democrats have not confirmed they'll attend. Among those invited are New York Gov. David Paterson, New York City Mayor Michael Bloomberg and Sen. Charles Schumer.
Rangel is running for reelection. A minimum campaign contribution of $200 is required to attend the party as a "special guest." But the best seats will presumably be reserved for "sponsors" who donate $2,500.
The ethics investigation has already cost Rangel his position as the chairman of a powerful House committee. On Tuesday, he insisted he is not corrupt and said he will not resign.
In a sometimes rambling speech, the New York Democrat defiantly challenged the House ethics committee to move faster on holding a public hearing on the 13 counts of alleged violations against him.
He also challenged fellow House members of both parties to kick him out if they want to get rid of him.
"If it is the judgment of the people here that I should resign," then the ethics committee should expedite its consideration of the charges, Rangel said.
But "I am not going away. I am here."
On July 29, the House ethics committee accused Rangel of 13 violations of House rules involving alleged financial wrongdoing and harming the credibility of Congress.
Among other things, Rangel has been accused of using his influence to solicit donations for a college policy center bearing his name from corporate heads and others with business before the powerful House Ways and Means Committee. Rangel was chairman of the committee until he was forced to give up the leadership position this year because of the pending allegations.
Other charges involve alleged income tax and financial disclosure violations, as well as improper use of government mail service and letterhead.
An ethics committee trial of Rangel is still set to be held, most likely in September, barring a settlement between Rangel and the committee members.
On Tuesday, Rangel offered explanations for the ethics charges against him, characterizing them as mistakes and acknowledging violations of House rules but denying they amounted to corruption.
"It's not corrupt," he said of using House letterhead for approaching possible contributors to a university policy center in his name. "It may be stupid. It may be negligent, but it's not corrupt."
Regarding an accusation that he used a rent-controlled apartment as a campaign office, Rangel said he did nothing wrong but was "insensitive to the appearance of being treated differently."
"I plead guilty of not being sensitive," he said.
He apologized "for any embarrassment I've caused," he said, but insisted he would retain his dignity despite the allegations.
"For God's sake, just don't believe that I don't have feelings, that I don't have pride," Rangel said, later adding: "You're not going to tell me to resign to make you feel comfortable."