It has happened. It has been a long time coming, and is being regarded by fans in fanatical, frantically excited terms in Facebook and Twitter posts alike. Ben Folds Five has reunited.

For over a decade, Ben Folds has been touring as a solo act and writing music on his own, songs not totally unlike Ben Folds Five, but lacking the extra oomph that bandmates Robert Sledge and Darren Jessee offered on bass and drums, respectively (though not all of his solo music was without bass and drums).

Right now, the reunion is no surprise; it has been in the works and out in the open for well over a year as the trio announced that they were recording a few new tracks together, which were later followed up by a full album announcement. The new record, “The Sound of the Life of the Mind,” is set to be released on Sept. 18. It is Ben Folds Five’s first full-length release since 1999’s “The Unauthorized Biography of Reinhold Messner.”

Last year, the group reunited briefly to record three songs for Ben Folds’ release, “The Best Imitation of Myself: A Retrospective.” Additionally, Ben Folds Five reunited for a single show in 2008, where they played their final album in its entirety.

Between the breakup and reunion, Sledge and Jessee have also kept themselves busy. Sledge formed a new group, Brother Seeker, and came close to serving as the replacement bass player for Weezer. Jessee formed the group Hotel Lights, which opened for Ben Folds at a handful of shows.

Folds also released an album co-written by English author Nick Hornby in 2010, titled “Lovely Avenue.”

The reunion tour in support of the new album brings Ben Folds Five to Mountain Park in Holyoke on Thursday, Sept. 13. The venue, the only Iron Horse Entertainment Group venue outside of Northampton, is an outdoor stage located on one side of Mt. Tom, just off of Rt. 5.

Mountain Park, which was once a popular amusement park, closed in 1987, according to the Iron Horse Entertainment Group website. The site offers a page full of old photographs of the amusement park in its heyday, including classic wooden roller coasters, a fun house and other classic attractions.

The trio will be joined by Kate Miller-Heidke, who has toured as an opening act for Ben Folds’ solo touring in the past.

Miller-Heidke, who hails from Brisbane, Australia, also has a new album out. Her album, “Nightflight,” was released in April 2012. Her official website offers brief explanations of each song on the album in the singer-songwriter’s own words. “Nightflight” is Miller-Heidke’s third full-length release. She has also released a handful of singles and an EP.

Her songs are beautifully written and performed, and Miller-Heidke earned kudos for her sense of humor with “Are You F***ing Kidding Me? (The Facebook Song),” written about an ex-boyfriend who friend-requested her on the social networking site after what sounds like a nasty breakup.

Ben Folds Five and Kate Miller-Heidke are performing this Thursday at Mountain Park, just off Rt. 5 in Holyoke. Tickets range in price from $30 to $55 and are available online and at the Northampton Box Office in downtown Northampton.

Ellie Rulon-Miller can be reached at [email protected].