VBA to open Access DB

I am trying to open an Access Database from a button within Excel.

However when I attempt to run it I get the following error:
Compile Error
User-defined type not definded

on - db As Access.Application


The code I am using is as follows:
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Dim db As Access.Application

Public Sub OpenDB()

Set db = New Access.Application
db.OpenCurrentDatabase "C:\Data\Report.accdb"
db.Application.Visible = True

End Sub