It hit number one on the Billboard Hot 100 on April 13, 1991, having hit number two in the United Kingdom the previous year. The song also topped the singles charts in Spain, Sweden, Germany, Switzerland, Austria and Australia.
Part of the song was sampled and prominently featured in the song "Physical" recorded by Alcazar.
7" single
- "I've Been Thinking About You" — 3:49
- "9 A.M." (live at Moles) — 5:49
- CD maxi
- "I've Been Thinking About You" (7" version) — 3:49
- "I've Been Thinking About You" (c'est wot mix) — 5:38
- "9AM" (live at Moles) — 5:49
- CD maxi - U.S.
- "I've Been Thinking About You" (def 12" mix) — 6:50
- "I've Been Thinking About You" (red zone mix) — 4:42
- "I've Been Thinking About You" (reprise) — 1:33
- "I've Been Thinking About You" (vocal dub) — 5:50
- "I've Been Thinking About You" (the eclipse mix) — 4:12
- "I've Been Thinking About You" (trak mix) — 3:05
- CD single
- "I've Been Thinking About You" — 3:49
- "9AM" (live at Moles) — 5:49
- 12" maxi
- "I've Been Thinking About You" (c'est wot mix)
- "I've Been Thinking About You" (force feel dub mix)
- "I've Been Thinking About You" (7" version)
- 12" maxi
- "I've Been Thinking About You" (extended club mix)
- "I've Been Thinking About You" (radio edit)
- "I've Been Thinking About You" (instrumental)
- "I've Been Thinking About You" (dub)
- Cassette
- "I've Been Thinking About You" (def 12" mix) — 6:50
- "I've Been Thinking About You" (red zone mix) — 4:42
- "I've Been Thinking About You" (reprise) — 1:33
- "I've Been Thinking About You" (vocal dub) — 5:50
- "I've Been Thinking About You" (the eclipse mix) — 4:12
- "I've Been Thinking About You" (trak mix) — 3:05