After the flop of ˝So Long˝, ˝I Do˝ made the Top 5 in most countries (#15 in the US) - except in the UK (only #38). ˝Rock Me˝ was the main B-side, except in North America (˝Bang-A-Boomerang˝), Holland (˝So Long˝, where that song hadn’t been released as A-side) and Brazil (a belated 1976 release b/w ˝Fernando˝, where the song wasn’t released as A-side).
In Peru the sides were merely switched.
In Turkey, ˝I Do˝ was coupled with ˝SOS˝, but is unclear which side is the A-side and when the single was released - see SOS.
˝I Do˝ appeared on ˝Greatest Hits˝ soon after the single release.
After ˝I Do˝ had hit #1 in Australia and New Zealand, the single was re-released there with ˝Rock Me˝ as A-side, reaching #4 and #2 respectively.
These successes and the fact that the track was in the setlist of the world tour in 1979 apparently resulted in the track appearing ˝Greatest Hits Vol. 2˝, as the only track not recorded between the years 1976 and 1979.