Clark, 75, has been recovering at his Malibu home from a Dec. 6 stroke.
"He's doing really well," Clark publicist Paul Shefrin said Monday. "He's walking. He's talking. He's living a fairly normal life."
The longtime host of "American Bandstand" (search) hasn't appeared on television or done interviews since his stroke. Last year, daytime talk-show host Regis Philbin stood in while Clark watched from his hospital bed.
"He just wants to fine-tune it before he sticks his head out -- makes his return to television," said Shefrin, who has refused to discuss the impact of what he would only describe as a minor stroke.
Clark said in a statement, "It will be good to be back in New York again for New Year's and I'm elated that Ryan has agreed to join me in ushering in New Year's."
Seacrest, host of "American Idol," (search) has agreed to a multiyear deal to executive produce and join Clark as co-host of the ABC special. Seacrest will eventually take over as host.
"Dick Clark is an American icon. I am honored that he has entrusted me with such a role in this national tradition," Seacrest said in a statement.