The 35-year-old actress's former husband Tom Cruise is a friend of Foxx, which is apparently making him concerned about keeping their romance hidden from the public, reported New York Post.
"Katie flew private to California to stay with Jamie at his home around the Grammys (on January 26). He and Holmes also spent time together during Super Bowl weekend, although they attended the game separately," a source said.
"Jamie is being careful because he has a lot of respect for Tom," the source added.