On Wednesday, former U.S. Vice President Al Gore will sit down with Apple's VP of Environment, Policy and Social Initiatives — Lisa Jackson — for a special event, hosted at the company's Union Square store in downtown San Francisco.

The pair will discuss "climate optimism," according to Apple, including "Earth Day initiatives," Apple's "ongoing commitment to the environment," and ways individuals can contribute. The event is scheduled for 7 p.m. Pacific time.

Attendance is free, but people wanting in must RSVP in advance. Video will likely appear at Apple's podcast store at a later date.

Gore is an unusually high-profile retail guest, in that the company normally hosts actors, authors, athletes, filmmakers, and musicians, rather than politicians.

In more recent years however Gore has become known for his environmental activism, including books and documentaries like "An Inconvenient Truth." More importantly, Gore has been a member of Apple's board of directors since 2003 — likely making it easy to put him on stage, assuming he didn't help arrange the event himself.