The veteran U.S. talk show host has presented The Late Show with David Letterman since 1982, but he announced last year (14) that he was retiring and being replaced by Stephen Colbert.

As his final episode aired, celebrities flocked to Twitter.com and Instagram.com to praise the star and commemorate their time spent on the show.

Martin wrote on the microblogging site, "Congratulations to David Letterman, who I now believe is beginning his third career in show business" while Patrick Harris shared, "I already miss David Letterman... #legendary"

Madonna, whose 1994 expletive-filled interview with Letterman became infamous, wrote on Instagram, "Awww Dave I'm gonna miss you! Where am i gonna go on T.V. When I wanna say the F word? do you still have my panties????"

Actor Jason Alexander paid homage, writing, "David Letterman, thank you for the laughs, both live and on air. May your family bring you joy and inspiration & may you laugh 4 all ur days" and Bette Midler added, "WOW! David Letterman is saying goodbye...33 years of superb invention on his part and laughter on ours. That went so fast! I loved it!!"

Fellow chat show host Conan O'Brien wrote, "It's absolutely absurd to thank David Letterman for all he's done in a tweet. But that's the world we live in now. #ThanksDave"

On Instagram, Kerry Washington shared, "...What an honor and a privilege and A JOY to be able to be your guest. You made me better. Every single time. #ThanksDave" while an emotional Elizabeth Banks writes, "He hasn't said a word and I'm crying. #ThanksDave"

Courtney Love sent a flirty message: "David @Letterman I will miss u and your freezing cold studio you have always been my favorite flirt and I adore you so much... #ThanksDave" and Cindy Crawford wrote, "Congrats to 33 years of making us laugh (and blush), @Letterman! We'll miss you! #ThanksDave"