EMail Validator with Regex

using System.Text.RegularExpressions;
public static class EMailValidator
{
	static Regex ValidEmailRegex = CreateValidEmailRegex();

	private static Regex CreateValidEmailRegex()
	{
		string validEmailPattern = @"^(?!\.)(""([^""\r\\]|\\[""\r\\])*""|"
				+ @"([-a-z0-9!#$%&'*+/=?^_`{|}~]|(?<!\.)\.)*)(?<!\.)"
				+ @"@[a-z0-9][\w\.-]*[a-z0-9]\.[a-z][a-z\.]*[a-z]$";

		return new Regex(validEmailPattern, RegexOptions.IgnoreCase);
	}

	internal static bool EmailIsValid(string emailAddress)
	{
		bool isValid = ValidEmailRegex.IsMatch(emailAddress);

		return isValid;
	}
}