"They both remain focused on their family and are jointly committed to their children,” his rep tells PEOPLE.
Gosselaar, 36, and Russell, 38, met on the set of Saved by the Bell when she had a small role. They got married in 1996, and have children Michael Charles, 6, and Ava Lorenn, 4.
No reason for the split was given. But a source close to the couple refuted Internet reports that Russell's behavior was to blame.
"The reports saying that she’s out partying aren’t true," says the source. "She’s a great mom. The two of them couldn’t be more hands on with the kids. Their number one focus is definitely their family."
Gosselaar next will be seen on TNT's new legal show Franklin & Bash.
Reporting by MICHELLE TAN