Mark Hoppus of Blink-182 and Plus 44 is working with All Time Low on their next record. Mark discussed the collaboration on his blog:

Last week I had All Time Low in the studio. They are working on songs for their new album and asked if I would be interested in co-writing with them. Co-writing is always an awkward experience at first. “Hey, how about you get into a studio with a bunch of people you’ve never met before and see what happens?”

So I had the basic outline of a song and alex came in and listened to it, liked it, and we got to work. Alex, Jack, Chris Holmes, and I grinded away at it, and three days later we walked out of the studio with what I think is a really great song.

Hoppus has worked as both producer and collaborator with a number of bands as of late, including Motion City Soundtrack and The Matches.
Source Mark Hoppus of Blink-182 and Plus 44 is working with All Time Low on their next record. Mark discussed the collaboration on his blog:

Last week I had All Time Low in the studio. They are working on songs for their new album and asked if I would be interested in co-writing with them. Co-writing is always an awkward experience at first. “Hey, how about you get into a studio with a bunch of people you’ve never met before and see what happens?”

So I had the basic outline of a song and alex came in and listened to it, liked it, and we got to work. Alex, Jack, Chris Holmes, and I grinded away at it, and three days later we walked out of the studio with what I think is a really great song.

Hoppus has worked as both producer and collaborator with a number of bands as of late, including Motion City Soundtrack and The Matches.
Source