Partially hides email address with PHP regex

I found two threads that at first seem to answer my query, but they only seem to be part of the solution to me. Using them, I got to where I am. So this is not a duplicate!

I want to replace everything except the first character in the name and domain part of an email address with an asterisk:

eg

g ****** @g ****. com or g ****** @g ****. co.uk

code:

$email2 = preg_replace('/(?<=.).(?=.*@)/', '*', $email);
$email3 = preg_replace('/(?<=@.)[a-zA-Z0-9-]*(?=(?:[.]|$))/', '*', $email2);

      

        
        
        
      

    

which almost exists, but gives me g ****** @g * .com , not g ****** @g *****. com

Can anyone help me with regex?