Glee star Criss took over from Radcliffe as J. Pierrepont Finch for a three-week stint. Nick Jonas will then step into the role on January 24.
Radcliffe told MTV News that while he has offered his support to Criss, the meeting between the pair was not recorded.
"We have met. I can confirm, we have met. Somebody showed me a very doctored photograph of our meeting; there were no photographs at our meeting, so if that's what people are interested in, they're going to be disappointed," the Harry Potter and Woman in Black star said.
"But no, I had a lovely chat with him, talked about the show, I don't really deign to give advice, but I gave him my number and same with Nick Jonas and said, you know, 'Contact me if you've got anything to ask. I'm always around'."
Radcliffe continued: "I passed on a joke to him that Matthew Broderick gave to me which Robert Morse gave to Matthew Broderick. So that's become sort of a legacy joke now, which is nice."
Criss recently promised fans that they will not notice his absence on Glee, revealing that he had filmed several episodes at once before departing for New York.
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