Mamma Mia! It's Mamma Mia! One part rom-com, one part musical and all parts awesome. Meryl Streep, Pierce Brosnan and Colin Firth star in this big screen adaptation of the phenomenally successful ABBA musical. You know the plot, you know the songs and you know you just can't get enough of Mamma Mia! which gets the pop-up treatment at Morden Hall Park. Good luck trying to stifle the urge to sing along. Our advice? Just let it all out. Mamma Mia! Be sure to wear appropriate clothing since the event is outside. Do bring something to sit on, don’t bring a tent.