Because this work was first published in 1929, both the music and lyrics became public domain in the USA as of January 1st, 2025. But in most other countries the issue is more involved due to the varied lifetimes of the three authors. The lyrics, by Andy Razaf (d.1973), will not become public domain in Canada until January 1st, 2044 but in the EU, its most likely PD there due to the Rule of the Shorter Term with the United States as the point of origin. However the music, co-composed by Fats Waller (d.1943) and Harry Brooks (d.1970), became public domain in Canada on January 1st, 2021 and will become public domain in the EU on January 1st, 2041, but these earlier dates apply only to editions not containing the lyrics.

This item, which is in the public domain in its country of origin, is likewise in the public domain in countries which apply the rule of the shorter term. All EU countries apply the rule of the shorter term in general.
Note that in some cases this rule may be overridden by a treaty with the source country (especially the United States) and/or may not apply to works which fell into the public domain in their source country due to a failure to renew copyright or comply with other formalities.