qadwjoh,
The answer(s) are yes. One use eval string which is typically frowned upon. The second would require you to tie a scalar. The 3rd option would be to use Interpolation and change your $var to a sub routine. The only reason for Interpolation is so that you can use it in a double quoted string.

None of these answers does it exactly the way you want. Take a look:

# Option 1
my $date = 'scalar localtime()';
print eval $date;

# Option 2
package Current_Date_Stamp;
sub TIESCALAR { bless {}, $_[0] }
sub STORE { return 1 }
sub FETCH { return scalar localtime() }
package main;
tie my $date, "Current_Date_Stamp";
print "The current date is $date\n";

# Option 3
use Interpolation date => sub {localtime()};
print "Today's date is $date{now}";
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Cheers - L~R