In a recent interview with Ryan Seacrest, Chris answered the million dollar collab question about Ariana, saying, "I would man, but she can sing so much better than me. I don't want to be humiliated in that fashion. I was in the car yesterday and 'Problem' was on. I was like, 'I just can't do that.'"
And we don't want you to, Chris. We'd be massively surprised by a Chris/Ariana duet because it doesn't make any sense, really. But it's interesting to get his take on it – he's pretty modest, no?