Us Weekly claims Rob and Andrew have a longstanding rivalry, with a source telling the mag, "The truth is, Andrew can't stand Rob."
Can't stand Rob? Even with his scroungy good looks and amazing man pout? We're amazed!
"Andrew hates that they're put in the same category because they're both English and around the same age," added the source.
Not even the wedding of their mutual producer pal Kevin Turen could bring the two boys together, with Rob (26) and Andrew (28) reportedly ignoring each other at the June event.
"They don't enjoy hanging out. Andrew considers himself a 'serious actor' and sees Rob as the equivalent of a cheesy boy bander because of Twilight," said one wedding insider.
Perhaps Andrew's forgotten about that equally cheesy Spiderman costume he's been wearing of late…