The former Blossom star was expected to join the outlandish Williams to promote his latest TV series Melissa and Joey but the 34 year old had to call in sick after catching a nasty cold from his eldest daughter Charleston.
But he delighted the studio audience by calling in from his sick bed to apologise for his absence.
He told Williams over the phone, "I got it bad. I have two children and my four-year-old girl got it (the flu). I had to take her to school because my wife - we have a six month old girl - she had to be quarantined so she didn't get sick, so of course I took her (Charleston, to school) and I got it! Four year old cooties are the worst, man!
"It's horribly bad so I apologise for not being there."