Credit: Gustavo Caballero/Getty Images; Christopher Peterson/BuzzFoto/FilmMagic

David Letterman - who outraged the Palin family last year by making off-color remarks about them -- made another series of quips on his late night show Wednesday -- only he kept his cracks milder this time.

Referring to Us Weekly's exclusive cover story in which Bristol, 19, admits getting engaged to Levi Johnston without her mother Sarah Palin's knowledge, Letterman, 63, joked that Johnston, 20, will arrive for the wedding tied to "Sarah Palin's pickup."

He also snipped that Bristol made the announcement on an "hour-long ESPN special," a reference to the channel's show on LeBron James.

He made fun of himself in his last joke. Mentioning Johnston's recent "heartfelt apology" to the Palins, he paused and told the audience: "That kind of rings a bell."

Last year, Letterman apologized to the Palins for crudely joking that one of the Palin kids got "knocked up by Alex Rodriguez."

Former Alaska Gov. Palin issued a statement calling the remark "sexually-perverted." Letterman later apologized, telling his audience, "I told a bad joke."