Orlando's Lord of the Rings co-star Elijah Wood starred with Nora in last year's Maniac Bloom and 30-year-old Kerr - who have two-year-old son Flynn together - announced in October that their three-year marriage has been over for a few months.
Orlando recently put his Los Angeles home in the Hollywood Hills on the market for £3 million.
Nora Arnezeder is usually called by her short or nick name Nora.