Yo-Yo Ma brought a special guest onstage Sunday night at Tanglewood: five-time Grammy winner James Taylor.

The two joined together to perform what Taylor called the only suite he’d ever write, “Sweet Baby James.” The surprise duet followed Ma’s playing of all Bach’s cello suites in a single concert (see review, below), as part of an initiative the legendary cellist — and Berkshires resident — calls the Bach Project.

Taylor and his wife, Kim, underwrote the concert at Tanglewood in memory of composer Andre Previn, who died in February. Previn, along with Ma, played at the Taylors’ wedding in 2001.

Isaac Feldberg can be reached at isaac.feldberg@globe.com. Follow him on Twitter at @isaacfeldberg.