updated 03/02/2013 AT 9:00 PM ET
•originally published 03/02/2013 AT 8:00 PM ET
The Duchess of Cambridge arrived at a wedding in a different kind of carriage Saturday – a bus.
They were there for the wedding of close friend and polo player Mark Tomlinson, who married Olympic equestrian Laura Bechtolsheimer in the town of Arosa.
Dressed in a pale coat accentuated with brown fur trim, a familiar James Lock hat and a Max Mara dress she’s wore previously underneath, an expectant Kate was seen walking “gingerly up the steps to the church,” an onlooker tells PEOPLE. “She was being very careful in her heels.”
Her husband William – in traditional tailcoat – had previously arrived due to his role as an usher at the ceremony.