How to remove button tooltip?

Below one is my code which has tooltip.. If at certain point I want to remove the tooltip, how to remove it dynamically?

Nothing should be shown on hover of button

Code:

Ext.create('Ext.Button', {
    text: 'Click me',
    tooltip: 'Tool tip Ex',
    renderTo: Ext.getBody(),
    handler: function() {
        alert('You clicked the button!');
    }
    
});