Barker, who hosted the quiz for 35 years, filmed a one-off special earlier this week (beg09Dec13) ahead of his milestone on Thursday (12Dec13), and was overwhelmed by the reaction he received on set.
He tells the New York Post, "I felt right at home. Even though they've changed the set quite a bit, it's beautiful and I could not have been more comfortable.
"That standing ovation brought a lump to my throat, it really did. I could hardly speak right at first. I was welcomed with such enthusiasm that it warmed the cockles of my heart.
"The whole experience was exciting for me. I only hope that the viewers who see the show will sense my comfort on the show, my happiness on the show and the fact that I really appreciate the opportunity to return to the show."
Barker retired from the show in 2007. The birthday special will be aired in the U.S. on Thursday.