Lumley, known for roles on TV series like "The New Avengers" and "Absolutely Fabulous," said Saturday before departing for Nepal she is looking forward to also meeting with former Gurkha soldiers during her weeklong visit.
"I don't think it can be anything other than wonderful," Lumley told the BBC.
"It's just incredible. I've never been to Nepal before, and this is really going to be just stunning," she added.
Lumley has been at the forefront of a campaign seeking United Kingdom residency rights for former Gurkha soldiers who served in the British military.
Peter Carroll, who began the campaign, will be accompanying the 63-year-old actress during her visit to Nepal, which will also include a meeting with Nepalese Prime Minister Madhav Kumar Nepal.
"I think it's going to be an amazingly emotional experience," Carroll told the BBC.