Will Ferrell's been revisiting his old hits lately, including this weekend -- when he teamed up with John C. Reilly to honor none other than Snoop Dogg ... who hit a big milestone.
Indeed ... the notorious 'Step Brothers' got together to sing one of their ditties from the movie Saturday night in L.A. -- where Will hosting some benefit concert at the Greek Theater, and where the two former costars got onstage to belt out a fan fave, 'Boats and Hoes.'
Fans of the film remember that one well -- only this time, a surprise guest was added to their lineup, and that'd be Snoop, who was celebrating his 52nd birthday from the day prior.
The performance, as it turns out, was mostly led by the Doggfather ... who fit in flawlessly.
You can tell Will and John really wanted to make Snoop feel special -- because at one point during all the fun, they presented him with a 3-tier birthday cake ... which SD was proud to show off on social media.
Great to see Snoop get his flowers -- but also, it's cool to see Will and John are still good pals. There were reports of bad blood a couple years back, but they're as close as ever.