In an interview on the Elvis Costello-hosted music talk show Spectacle a few years ago, Elton John made it clear how much he thought of Leon Russell, the fellow piano man who was churning out hits like “A Song For You” and “Delta Lady” while John was still his opening act. Although their career trajectories have diverged from that point, the bond they forged back then comes to fruition on their new collaboration, The Union.

The temptation would be to view this as a bit of musical philanthropy on John’s part, trying to prop up a former idol who hasn’t been in the spotlight for a while and who was also coming off brain surgery right before the recording of the album. But Russell comes right out of the box and proves he’s in fighting shape with album-opening “If It Wasn’t For Bad," a sultry, minor-key-drenched killer of a single that sounds like it could have come right in sequence with Russell’s other early 1970s successes.

John follows that right up with “Eight Hundred Dollar Shoes,” a soulful yet cutting track that sounds like it could have come from his own streak of ultra-successful albums in the '70s with lyricist Bernie Taupin. (Taupin, John, Russell all share writing credits on the album along with producer du jour T-Bone Burnett.)

It doesn’t take long to sense a rejuvenated Elton, as he burns through the stomping “Hey Ahab” with the force of someone auditioning for his first break. Maybe his hero worship of Russell has never abated, because John is performing here like he’s the one with something to prove.

You might expect The Union to rely too much on piano to provide the musical heft, and indeed some of the up-tempo numbers like “Monkey Suit”, featuring the pair dueling like the boogie virtuosos they are, sound as if they might be more fun as live jams than they come across on record. There are stylistic curveballs throughout keeping things lively though, including the Civil War dirge “Gone To Shiloh,” which guest stars Neil Young.

On a track steeped in American history, it only makes sense that Russell, John, and Young’s doleful harmonies ape The Band’s terrific trio of Levon Helm, Rick Danko, and Richard Manuel.

The Union really finds its footing when the two men ruminate on love gone wrong. John belts out the stirring chorus of “When Love Is Dying” with a desperation that plays nicely off Russell’s matter-of-fact observations. They follow that up with the darkly eloquent “I Should Have Sent Roses,” harmonizing beautifully over lines about missed opportunities and time wasted.

Evident throughout is the fondness the two men seem to have for each other. The two talk frankly about getting old on “The Best Part Of The Day” and “Never Too Old (To Hold Somebody),” but they lean on friendship to get them through the hardest parts. As Russell sings on the latter of those two gems, “You’re still sharp as a razor/And I like you like that.”

I would say that fans of these two men with such distinctive yet prodigious talents will echo those sentiments exactly upon hearing this album.

On the album’s closing number, the gospel-tinged “The Hands Of Angels,” Russell seems to be thanking John for pulling him out his funk. Elton should be equally thankful though, because his fervor to help out his mentor has pulled him out of his life as a full-time celebrity and returned him to being a relevant musical force.

The Union may be the product of a mutual admiration society, but what it yields is not just nostalgia from two men thought to be well past their primes. In truth, it is compelling music worthy of standing alongside some of the best the pair has created.