Data analysis of digital sales, radio play and Web traffic by the Nielsen Company reveals the full impact of an appearance on U.K. music talent show "The X Factor" in the U.K.

The ITV1 show secured big names as guest performers on the Sunday night results show during Q4 in 2009, including Whitney Houston, Alicia Keys and Michael Buble.

U.K. digital download sales for those artists performing either had strong first week sales following the performance, or sales spiked for tracks which had already been available.

Cheryl Cole, show judge and member of pop act Girls Aloud, had the biggest weekly download sale following an "X Factor" performance - 221,000 for "Fight For This Love" (Polydor/Universal). Former contestants Alexandra Burke and JLS had the second and third biggest digital track sale respectively, following an "X Factor" performance.

Black Eyed Peas' "Meet Me Halfway" had been available 22 weeks prior to their Nov. 8 performance on "The X Factor," but the appearance on the show still sent it to No. 1 with 79,700 digital sales. It was the fourth biggest digital sale post-"X Factor," followed by Leona Lewis's then new release "Happy" (Syco/Sony Music) which sold 67,400.

Other acts to benefit from the performance for songs available more than a week before the broadcast include Shakira, whose "Did It Again" (Sony Music) increased sales by 358% in the week following the show. Sales of Michael Buble's "Cry Me A River" (Reprise/Warner) increased 323%, according to analysis by the Nielsen Company.

It also measured online buzz and found that for almost all the 18 guest stars, online buzz in the U.K. increased after the performance.

Nielsen Music Control data showed that Mariah Carey's "I Want To Know What Love Is" (Island/Universal) had the biggest increase in radio airplay, with an increase of 297% for plays of the track.