I don't mean to sound rude, but don't ask for something like that.
If he wanted fans to have his number, then they would have it. Celebrities have their own lives and things to do, and if their fans all had their number they would never be able to get anything done.
It's honestly disrespectful to Jack directly, if you were a real fan you wouldn't go around asking for his number. It's his own private information and its not to be shared.
Again, no offence intended, I'm just saying.