David Crosby and Americana sensation Jason Isbell have been tweeting some not-so-subtle hints about a possible collaboration in the studio between the two songwriters.

It all started this past Tuesday when Isbell tweeted, “brought a ringer into the studio to sing” and attached a picture of himself and most of Crosby’s head. The two looked fairly pleased to be in the same room together.

Related: David Crosby & The Lighthouse Band Perform For NPR ‘Tiny Desk Concert’ [Watch]

As if that wasn’t obvious enough, Crosby added flames to the fire Thursday by tweeting back, “Lucky me ….I’m goin to sing with Jason and Amanda”, referring to Amanda Shires from Isbell’s band The 400 Unit, followed by more folksy excitement that hopefully doesn’t prove to be more of Crosby’s brand of biting sarcasm.

In addition to possible studio collaboration, Crosby continued to ruin his publicist’s day by telling a random fan with 89 followers on Twitter that he “believe[s]” he and Isbell will share the stage again this summer in New York City and Washington D.C., but gave no specific dates.

At last summer’s Newport Folk Festival, Crosby made a surprise appearance during Isbell’s headlining set with The 400 Unit, where the two performed Crosby, Stills, & Nash classics “Wooden Ships” and “Ohio”. Then this past September, Crosby opened up for Jason Isbell and The 400 Unit at Colorado’s Red Rocks Amphitheatre, and the two traded sit-ins during the other’s set. They once again covered the CSN staples “Wooden Ships” and “Ohio”.

In the time since, and even before, those sit-ins, Crosby and Isbell have been flirting on twitter by sending praise back-and forth or just plain saying “hi” while poking fun at Neil Young.

Jason Isbell and the 400 Unit are back on the road now, after apparently doing some studio work, touring the U.S. through the rest of December and into January until they go overseas for Billboard Live in Tokyo after which they’ll return to the states, playing dates the rest of January before a brief break until the end of February. Tickets are available here.

Meanwhile, Crosby’s schedule is wide open until May 14th when he begins a five-week tour of the United States, with a lone stop in Canada for Toronto Jazz Fest June 18th. Tickets for those shows are available here.