 <p>I believe if you define user inside UserProfile, then you can access it and will automatically be mapped? It works in my previous projects, I hope it will work with this.</p> <pre><code>сlass UserProfile { String fio String position String phone String email static belongsTo = [user: User] User userInstance; static constraints = { // some constraints } </code></pre> <p>Then you can use it</p> <pre><code>UserProfile.executeQuery("select up.userInstance from UserProfile up") </code></pre>