How to convert a "HH:MM:SS" string to seconds with PHP?

Is there a native way of doing "HH:MM:SS" to seconds with PHP 5.3 rather than doing a split on the colon's and multipling out each section the relevant number to calculate the seconds?

For example in Python you can do :

string time = "00:01:05";
double seconds = TimeSpan.Parse(time).TotalSeconds;