The real Neil Young turned down an offer to appear on Late Night With Jimmy Fallon and perform alongside Fallon’s hysterical impersonation of his After The Goldrush-era self. Bruce Springsteen had no such reservations, and in 2010 even agreed to dress up like himself circa Born to Run and sing a cover of Willow Smith’s “Whip My Hair” alongside faux-Neil. The Late Night staff did such a good job recreating Springsteen’s old look that even hardcore fans took a few seconds to realize they were looking at the real deal and not an impostor.

Bono broke his shoulder on the 1987 Joshua Tree tour and often invited fans onstage to play guitar in his place. When the tour hit Philadelphia's JFK Stadium Bono brought Springsteen onstage to play "Stand By Me" with U2.  "Is he a local boy or something?" Bono teased the crowd as they went ballistic.

Springsteen's final tour with the E Street Band before their decade-long hiatus was for Amnesty International in 1988. Sting came out many nights to perform "The River." Years later Springsteen said he was partially inspired to break up The E Street Band when he saw what Sting was able to do outside of the confines of The Police while on that tour.

Axl Rose delivered a moving speech for his hero Elton John at the 1994 Rock and Roll Hall of Fame induction ceremony. Later that night he was coaxed onstage to sing the Beatles classic “Come Together” with Springsteen. Rose didn’t perform again in public for six years.

Melissa Etheridge has cited this 1995 duet with Springsteen on "Thunder Road" as the highlight of her career. She was so nervous that she flubbed the words during the first run-through and they had to start  again.

In 1973 Bruce Springsteen and the E Street Band backed Chuck Berry at a now-legendary gig in College Park, Maryland. Sadly, no audio or video survived from the show – but 22 years later they teamed up again at The Concert for the Rock and Roll Hall of Fame at Cleveland Stadium.

Early on his career Springsteen was constantly tagged as another "New Bob Dylan," which irritated him to no end. At the 1997 MTV Music Awards he shared the stage with the Nineties' "New Bob Dylan" – his son Jakob Dylan. 

In the ultimate New Jersey rock moment, Jon Bon Jovi joined Springsteen onstage for "It's My Life" at one of the traditional Springsteen Asbury Park Christmas shows in 2003.

Just a few months after Joe Strummer's sudden death, Springsteen played tribute to him at the 2003 Grammys with a ferocious cover of "London Calling" alongside Little Steven, Dave Grohl and Elvis Costello.

Neil Young didn’t officially participate in the 2004 Vote for Change tour, but he made surprise appearances with most of the performers at various tour stops. In Minnesota he joined Springsteen and the E Street Band for a powerful “Rockin’ in the Free World.” Bruce and Neil have played together a number of times, but this is their most intense encounter.

The Vote for Change Tour was heavy on collaborations, but few were as memorable as Springsteen and R.E.M.'s nightly duet of "Man on the Moon." Hearing Springsteen sing the line "Mr. Andy Kauffman's gone wrestling" was about as cool as it gets.

An Ottawa fan near the camera in this clip summed this shocking moment up quite nicely: "Oh my god! What the fuck?" It was one thing to see Win Butler and Regine Chassasgne come out at a 2007 Springsteen show for "State Trooper," but when the E Street Band started into Arcade Fire's "Keep The Car Running" Springsteen's hipster cred reached a new high.

Springsteen has always cited the Byrds' 1965 debut LP as one of his all-time favorites, and at an Orlando tour stop in 2008 he finally got to sing "Turn! Turn! Turn!" and "Mr. Tambourine Man" with their frontman Roger McGuinn.

Rage Against the Machine covered Springsteen's "The Ghost of Tom Joad" on their 2000 covers disc Renegades, and Rage guitarist Tom Morello joined Springsteen and the E Street Band many times on the Magic tour to perform the song. There's no shortage of guitarists in the E Street Band, but Morello's stunning solo added a whole other dimension to their sound.

The ultimate union of Long Island and New Jersey occurred at a 2008 New York fundraiser for Barack Obama when Springsteen and Billy Joel formed a supergroup and sang each others’ hits to the high-rolling crowd. At the Rock and Roll Hall of Fame’s 25th anniversary shows at Madison Square Garden in 2009 they came together again on “New York State of Mind.”

Soul legend Sam Moore has played with Sprinsgteen many times onstage and in the studio, but their greatest work together is this Sam and Dave medley from the Rock and Roll Hall of Fame's 25th anniversary concert in 2009.

The 2010 Rainforest Benefit saw Elton John sing "Like a Virgin," Sting cover the Fine Young Cannibals and surprise guest Bruce Springsteen's soul-infused cover of Bryan Adams' "Cuts Like A Knife" – but nobody was prepared for the grand finale of Journey's "Don't Stop Believin'" with Lady Gaga and Springsteen trading lead vocals. In four decades of Springsteen collaborations, this was the nuttiest.

Believe it or not, Bob Seger and Bruce Springsteen have only performed together on two occasions. Seger came out onstage in Michigan on the opening night of the River tour in 1980 for the final encore of "Thunder Road," and 31 years later Springsteen returned the favor by joining Seger at Madison Square Garden for "Old Time Rock & Roll." It was worth the wait.