As the guest, you should honor the bride and groom's wishes and dress appropriately for the ceremony. Be aware that some houses of worship do not allow women to have bare shoulders. If you've decided to wear a strapless dress, just make sure you bring a pashmina or sweater to cover up during the ceremony. This is a sign of respect and you can always remove the sweater once you arrive at the reception.

If you're unsure of how to dress, try asking another friend who's been invite, the maid of honor or the bride herself. They will be able to fill you in on what's acceptable. In a pinch, err on the safe side and dress modestly for a church ceremony. You almost can't go wrong if you bring along an extra sweater or shawl.

Read more about guest attire:
Are there guest style guidelines for a wedding?
Is it okay to wear red to a daytime wedding?