The retail space has been set up by the nonprofit Help Refugees in the Covent Garden area of the English capital, and the 46-year-old star was on hand with a large cafetiere to serve refreshments to customers.
Dressed in a branded Choose Love hoodie, the Cersei Lannister actress handed out disposable coffee cups emblazoned with the Choose Love logo, as fans queued to buy blankets, shoes or tents for refugees who have just arrived in new countries, or food and education for those who have asylum.
Gushing over the "gorgeous" shop to Sky News, Lena explained, "It's a beautiful concept. You come in to Choose Love store which is gorgeous."
"You can get a hot cup of coffee and you can buy anything from blankets to warm winter shoes for kids for adults. You can buy an entire tent set up because people right now need to sleep on something other than the cold wet ground," she continued. "You leave with nothing apart from knowing that you have done something wonderful for someone who really needed it."
The Choose Love pop up will remain open until Christmas Eve, December 24.