During Mark's appearance on Watch What Happens Live! on Sunday, a caller asked him his thoughts about Justin crushing on his wife of 19 years.
"I thought it was fantastic," the 44-year-old actor gamely replied. "I agreed with what he said; she makes me feel a certain way as well."
When fellow guest Christina Applegate commented, "Yeah, he's bold, that little one," Mark explained his laid-back response.
"I know, but what are you going to do? Be angry at Justin Bieber?" he said. "You can't be angry at Justin Bieber."
Mark and Kelly have been married since 1996, and have three children together -- 18-year-old Michael Joseph, 14-year-old Lola Grace, and 12-year-old Joaquin Antonio. Last month, Kelly responded to Bieber's surprising Instagram post on Live With Kelly and Michael, and revealed her daughter to be a big Bieber fan.