The 54-year-old singer wanted permission from the singer to include his spoof song 'Handy' on new album 'Mandatory Fun' but with time running out to get the track approved in time, he took matters into his own hands.
He exclusively told BANG Showbiz: ''We contacted her management office and we felt we'd hear back right away but we didn't ... The clock was ticking.
''Finally I decided if I wanted to get this album out, ... I just needed to track her down in person. So I flew out to Denver where she was doing this show and I waited by the side of the stage.
''As she walked off stage, I introduced myself and said 'Hi, we're supposed to be going to the studio tomorrow to record my new song ['Handy'] and I just wanna make sure that you're ok with that'.
''I showed her the lyrics, she looked at them and said 'seems fine' ... I got back on the plane the next morning and recorded the song.''
The 'White and Nerdy' hitmaker hasn't always been given permission to parody songs - but insists that in the case of James Blunt, it worked out for the better.
He said: ''A couple of albums ago, I wanted to do a parody of 'You're Beautiful' by James Blunt called 'You're Pitiful'. James had signed off on it but his record label, Atlantic Records, had told me they did not want me to release the song.
''I didn't want any drama and complications ... so we decided to back off. Actually, they did me a favour because that was originally the single off my album and instead we released 'White and Nerdy' which became my biggest hit ever. It was a top 10 single, a platinum selling single.''
Weird Al's new album 'Mandatory Fun', which features the song 'Handy', is out now.
The acclaimed performer had just cancelled touring due to a battle with cancer.
Many ticket-holders couldn't get into the O2 Arena show on Tuesday night (September 19th) because they didn't bring photo ID to match their booking.