David Letterman 'regrets' Sarah Palin joke

David Letterman has revealed that he regrets telling jokes about Sarah Palin’s daughter.

The Late Show host has denied that the quips were aimed at Palin's 14-year-old Willow, but were instead intended for the politician's eldest, Bristol, 18, TV Guide reports.

"Were the jokes in question in questionable taste? Of course they were. Would I do anything to advocate or contribute to underage sexual abuse or misconduct? Absolutely not, not in a thousand years," he said.

Letterman has made several jokes aimed at Bristol's out-of-wedlock pregnancy, which have included references to the family’s recent attendance at a New York Yankees baseball game.

"There was one awkward moment during the seventh-inning stretch when her daughter was knocked up by Alex Rodriguez," he said.

Palin and husband Todd have called the chatshow host’s references "sexually perverted" and "despicable".

Letterman has invited the Palins to appear on his programme.