The actor, who plays Jasper in the supernatural film series, will appear as an ex-convict named Nate Osbourne in an upcoming episode of the Matt Bomer show.
The character is said to be part of a Bonnie and Clyde-esque partnership with his girlfriend, played by Jessica McNamee.
According to The Huffington Post, the pair break out of jail and into an event that Neal (Bomer) and Sara (Hilarie Burton) are attending.
The casting news comes after Rathbone welcomed a baby boy with girlfriend Sheila Hafsadi early in July.
White Collar's fourth season continues Tuesdays at 8/9c on USA.