An expandable sheath assembly includes a support body extending from a proximal end to a distal end. A guide rod is interconnected to the support body and extends between the ends along an axis. A dilator extends from the guide rod for insertion into a body vessel, and a hub is releasable connected to the distal end of the support body. A distal sheath overlays the dilator, and a hemostatic valve is slidably disposed along the axis. A proximal sheath extends from the hemostatic valve and is disposed in surrounding and coaxial relationship with the guide rod. The proximal sheath is concurrently slidable with the hemostatic valve along axis to advance the proximal sheath through the hub and interleave the proximal sheath between the dilator and the distal sheath for lifting the distal sheath from the dilator and effectuating an expansion of the body vessel.