I think he would be rather too busy to come, what with his... escapades in outer space. There is also the matter of his young pup. His spouse is rather unhappy with his extended absences, come to that.

[There is a faint hint of amusement in her face at this. That's what you get, Taning, for being away far too long from your frankly quite wonderful wife. Lionesses don't like it when the lion isn't around.]