The pair play Jacob and Bella in the hit vampire franchise, which is drawing to a close with upcoming final instalment Breaking Dawn - Part 2.
Taylor told US Cosmopolitan that Kristen - who is said to be rekindling her romance with Twilight heartthrob Robert Pattinson after a fling with married director Rupert Sanders - was "fantastic at everything she does".
He added: "I'm always proud of her."
Taylor, who said he had never been involved in a cheating situation, reckons it's possible to reconnect with an ex-partner.
He revealed: "If it was a long, serious relationship, I think it's quite easy to rekindle. I guess it depends on what damage has been done."
The 20-year-old added: "There's no ex out there who I'm not friends with today and I'm extremely thankful for that."