The late evening disrupt the TV presenter when he grilled on his visit to the prison last year, and refused to change the subject when begged Hilton.
So when Paris Hilton has agreed to return to Letterman "The Late Show" to promote his new film "The Hottie & The Nottie ', the host country decided it was time to make amends.
Before introducing the hotel heiress, Letterman said: "I made a fool of myself and I find it difficult to women's feelings. I went too far. "
The reception was adamant Hilton revealed that she had never appear on the new show, but he also went to decline to apologize, sent her a letter and flowers, and begs her to change her mind: " I said… I want to apologize to you in person.
"In 26 years of being on the air, I have offended thousands of people… Paris but, God bless her, has the spine and coming on the show."
True to his word, Letterman began his discussion with Paris Hilton by apologizing for his behaviour during their previous meeting, which prompted his smile guest to say: "I hope you got the whole prison thing out of your system. "
And the chat moderator was at its best behaviour, chatting at the Hilton Hotel about his new film and helping to promote its own sparkling wine, and portable video games footwear, jewellery, watches, clothes and Perfume.
The excited had some kind words for the host when he asked if she was happy to be back, saying: "You are really well behaved so far. You may not be nasty. "
And after the swearing her return, Letterman presented with a bouquet of flowers for Paris Hilton .