Frankie Muniz has shared his thoughts on Erik Per Sullivan's decision not to reprise his role as Dewey in the upcoming Malcolm in the Middle revival.

The actor's screen brother has revealed that the news did not come as a shock.

"He's very happy in the life that he's created outside of the entertainment world," Muniz told The New York Post. "He made the decision that he didn't want to get back into it - which we completely respect."

Muniz said the rest of the cast - including his TV parents, Bryan Cranston and Jane Kaczmarek - had no intention of trying to talk Per Sullivan into "something he didn't want to do".

"We had his blessing from day one to have the role be in the show and recast it," the former child star added.

"So I hope people aren't too upset that he didn't come back, but it was by his choice."

Per Sullivan quit Hollywood after starring in the sitcom from 2000 to 2006.

Fargo and The Expanse star Caleb Ellsworth-Clark takes over the role of Dewey in the upcoming revival, which is set to air in 2026.

"We knew early on that Erik was not going to be a part of it," Muniz added.

But he said that reuniting with the rest of the cast felt like a dream come true.

"It was as if no time had passed, for everybody," he said. "Justin (Berfield), who plays Reece, he's been out of the acting world for years. But he was right in back into the character. Obviously, Bryan Cranston is Bryan Cranston - probably one of the greatest actors ever. Everybody just fell right back into it."