The Hollywood superstars are splitting after five years of marriage.
Katie's attorney Jonathan Wolfe today said: "This is a personal and private matter for Katie and her family.
"Katie's primary concern remains, as it always has been, her daughter's best interest."
Katie, 33, and Tom, 49, have one daughter together, six-year-old Suri.
Katie was tellingly missing from the Rock of Ages premieres in London and Los Angeles this month.
Actor Tom, who stars in the film as outlandish singer Stacee Jaxx, walked the red carpet alone and told reporters his wife had business to attend to in China and couldn't change her schedule.
Tom is now preparing to spend his 50th birthday on Tuesday with son Connor in Iceland, where he is filming new movie Oblivion.