There are four months left before David Letterman takes his final bow on The Late Show with David Letterman on May 20. That doesn’t leave Jay Leno a whole lot of time to finally appear as a guest with Letterman on his show.

According to TV Insider, The Late Show has reached out to Leno to appear on the show before Letterman’s retirement. The request was made a year ago, when Leno was wrapping up his own Tonight Show run, and will likely be renewed.

The last time to two were together was during a Super Bowl ad, along with Oprah Winfrey, on CBS for The Late Show in 2010.

Before that, it was in 1992, when Leno appeared as a guest on Letterman’s old show, NBC’s Late Night with David Letterman, three weeks before Leno replaced the legendary Johnny Carson on The Tonight Show, the decision of which caused the decades-long rivalry between the two late-night talk show hosts.

Letterman has never appeared as a guest during Leno’s run on The Tonight Show and Leno has never appeared on CBS’s The Late Show with David Letterman.

Leno has previously said that he would be open to the idea of appearing on The Late Show, telling TV Insider that, “It’s certainly a possibility. Some of my best moments were doing the show with Dave.”

With the clock now ticking, we might finally get to see a long-awaited, historic reunion between the two late-night titans.