Foreigner's next album, "Agent Provocateur", co-produced by Alex Sadkin, was released in December 1984 and in 1985 gave them their first and only No. 1 hit song in the US and several other countries (except for Canada were "Urgent" had done the trick) when "I Want to Know What Love Is", a ballad backed by Jennifer Holliday and the New Jersey Mass Choir, topped the charts in the US (both Hot 100 and Rock Tracks), UK, Canada, Australia, New Zealand, Norway, Sweden, etc. while hitting No. 3 in Germany (their only Top 10 hit there), No. 4 in France (their only Top 20 hit there) and No. 6 in both the Netherlands and Belgium. "That Was Yesterday" was the next single from the album in early 1985 and proved to be another sizable hit reaching No. 12 on the US Hot 100 (No. 4 on Rock Tracks) and the Top 30 in several other countries. The album was equally successful becoming Foreigner's only No. 1 album in the UK, Germany and Norway while reaching No. 3 in Australia (its biggest album there) and Canada, and No. 4 in the US and New Zealand (its biggest album there). It was certified 3x platinum in the US, their lowest selling album to date in that country.