Creating Slice from Reflected Type

I am trying to create a slice from a reflect.Type. This is what I have so far.

package main

import (
    "fmt"
    "reflect"
)

type TestStruct struct {
    TestStr string
}

func main() {
    elemType := reflect.TypeOf(TestStruct{})

    elemSlice := reflect.New(reflect.SliceOf(elemType)).Interface()

    elemSlice = append(elemSlice, TestStruct{"Testing"})

    fmt.Printf("%+v\n", elemSlice)

}

However I get the following error and I'm not sure how to get around it without hardcoding a conversion to []TestStruct.

prog.go:17: first argument to append must be slice; have interface {}

Is there anyway to treat the returned interface as a slice without having to hardcode the conversion from interface{} to []TestStruct?