Chris Pratt and Katherine Schwarzenegger have a baby on the way -- their first together ... which means Arnold Schwarzenegger will be a newly-minted grandparent too. TMZ has confirmed the married couple is expecting, though it's unclear how far along Kat might be at the moment. Reports surfaced last year that they were eager to get their family started as soon as possible -- they got hitched just last June after about a year of dating.