Chart-topper You're The One That I Want has been revealed as the biggest selling duet of all time - more than 30 years after it was a hit.
And Olivia Newton-John and John Travolta, who sang the track, pulled off a double feat with their other hit, Summer Nights, placed second.
The chart of all-time best-selling duets will be counted down in a Radio 2 special presented by DJ Tony Blackburn.
Newton-John and Travolta's hits were both recorded for 1978 blockbuster movie Grease, and both went to number one in the UK chart.
The success of You're The One That I Want - at number one for nine weeks - led to a notable spoof version by Arthur Mullard and Hylda Baker.
The chart - compiled for the station by the Official Chart Company - does contain some surprises. Novelty hit Whispering Grass by It Ain't Half Hot Mum stars Windsor Davies and Don Estelle is at number six.
Jason Donovan and Kylie Minogue were placed fourth for their 80s' hit Especially for You, while Faith Evans and Puff Daddy were third with I'll Be Missing You - a tribute to Evans' late husband Christopher Wallace, aka The Notorious B.I.G.
The top 50 includes two artists who feature three times with different partners. Barbra Streisand accompanies Celine Dion, Neil Diamond and Donna Summer, while Sarah Brightman partners Paul Miles Kingston, Andrea Bocelli and Sir Cliff Richard.
The oldest track in the top 10 is Sir Elton John's collaboration with Kiki Dee, Don't Go Breaking My Heart from 1976.
Jane Birkin and Serge Gainsbourg's saucy single, Je T'aime, Moi Non Plus, which was banned by the BBC, is at number 15.