The OneRepublic star contributed heavily to Adele's second album, and has since been in the studio with her working on the long-awaited follow-up.
"I haven’t heard everything she’s done, but I’ve heard everything we’ve done and I’m as proud of it, or prouder of anything we did on [21], and she is sounding even better than ever," he told MSN Music.
Quizzed on when the album is likely to be released, Tedder replied: "She will deliver the album on her own timetable, at her own pace, and the only person that will ever declare it finished will be her, when she decides it’s finished."
Earlier this year, it was revealed that Phil Collins had also been working on the record.
"I've just started to work with Adele. She contacted me to write together," he revealed. "I wasn't actually too aware [of her]. I live in a cave [but] she's achieved an incredible amount and I really love her voice and I love some of that stuff she's done. So, to me, it's always an eye-opener - educational."
It is hoped that Adele will release her new album later in 2014, with tour dates and perhaps a Glastonbury appearance also rumoured.