Thinking Fox had already made the announcement, Smart confirmed the news to E! Friday.
The tenth and eleventh-season judge took a break from the reality competition last year, but a source told E! she wanted to take back her judging duties so she could have more time for new film and television projects.
"And, of course, her twins are starting school this year and she will have time for her family," said the source, whose name was not reported.
DISCUSS AND COMMENT ON THIS STORY Reality TV World now offers Facebook Comments on our stories. To post a comment, log into Facebook and then 'Add' your comment. To report spam or abuse, click the 'X' in the upper right corner of the comment box.