Loop until the last column in a row and fill comboBox

How to fill my ComboBox1 with all the values of a row without blanks from B2 until the End of the row?

I know :

Sheets("Sheetname").Range("A2:A"& .Range("A65536").End(xlUp).Row).Value

but this is the code to loop until the last row in a column, I want to do the opposite.