Conversion failed when converting the varchar value 'xxxx' to data type int.

Hi,

I have a table for R&D which has following cols:

EmpID|EmpName|EmpLname|

and i want to insert values using parameters from Stored procedure as:

declare @EMPID int;
declare @EmpName varchar(50);
Declare @EmpLname varchar(50);
Declare @aa varchar(max);

set @EmpId=6;
set @EmpName='Ramesh';
set @EmpLname='Kumar';
set @aa='insert into Employee(EMPID,EMPNAME,EMPLname) select '+@EMPID+','+@EmpName+','+@EmpLname+ ' from  Employee'
Print @aa


once executing, 
I am getting following error:

Conversion failed when converting the varchar value 'insert into Employee(EMPID,EMPNAME,EMPLname) select ' to data type int.

Kindly Suggest