That's not Mac, it's an ex UFC fighter playing Dennis. They had a preview on Facebook in which they re-cast everyone,
http://www.facebook.com/photo.php?v=4619121404861
Charlie with Candice Cameron, Dee with Xibit, Mac was Haley Joel Osment and Frank was Andrew Dice Clay. I'm looking forward to the premier as well, last season had some great moments, but some weak ones as well, we'll see how many good seasons they have left