The 24 year old announced she had separated with Alex in December 2010, and papers filed on October 20 at the Los Angeles Superior Court cite irreconcilable differences as the reason behind the split.
The pair - who married in secret in December 2009 - are seeking joint custody of their 20-month-old son Jackson.
Jim's spokesperson Marleah Leslie said last year the couple intended to stay in close contact.
She told People: "The couple will remain friends, as well as devoted parents to their son Jackson Riley.
'Dumb & Dumber' actor Jim has previously revealed he can see a lot of himself in his grandson as he is "very funny".
He said: "He's got this mischief on his face that you can just tell that he knows he's going to be completely accepted in every way, you know? It's just full on, 'I am it. I know you want to see me. I know whenever I say hi, everybody's going to laugh'.
"But he's very funny, too. Yesterday it was the sunglasses, putting the sunglasses upside down. And that totally reminded me of me because I was a very finicky eater, and my mother said that I got out of eating every time by just making everybody laugh and everybody howl at the table."