David Letterman Appearing at New Fundraiser for Biden Amid Campaign Woes

President Biden ain't throwing in the towel just yet -- 'cause top-level Dems are throwing another big fundraiser for him in the near future ... and David Letterman's going.

The news just came down from AP -- which says Hawaii Gov. Josh Green is hosting the shindig for Joe on July 29 out in Martha's Vineyard ... where they'll be hanging out at a private home that apparently belongs to a friend of Green's.

In terms of DL's involvement ... word is, he's set to headline the get-together -- so, in other words, he'll be the talent ... and probably moderate things as the emcee.

Unclear if any other celebs will be in attendance -- but the fact this fundraiser will be happening at a residence as opposed to a facility ... it kinda suggests this might be relatively small with a tight-knit group ... in contrast to the ritzy ones hosted here in L.A. and NY.

More importantly though ... it also signals that the Biden campaign has been right all along this week -- namely, that their boss isn't in fact dropping out of the race despite speculation.

As you know ... there's been a growing drumbeat of Dems demanding Biden step aside and make way for younger blood ahead of the November election -- but the fact they're whipping up donors for yet another round of fundraising strongly implies ... Joe ain't going anywhere.

Of course, he's sidelined right now with COVID -- but there's already a hard date for him to get back in the mix ... and all signs point to him trying to rally and score fresh cash.