In 1994, she starred as Sandy in a West End revival of the musical Grease, while on television she appeared as Bunty in the 1998 BBC comedy series The Lily Savage Show.

[6] All five singles released from the album became top 20 hits in the UK,[3] making Sonia the first British solo female artist to achieve this.

Sonia achieved a sixth top 20 hit in the UK in 1990 with "You've Got a Friend",[3] recorded with the group Big Fun, and released as a charity single for Childline.

The first single released from it, "Only Fools (Never Fall in Love)" became Sonia's third UK top 10 hit,[3] although the album was less successful than her debut.

In 1993, Sonia represented the United Kingdom in the 1993 Eurovision Song Contest, singing the Dean Collinson and Brian Teasdale composition "Better the Devil You Know".

Sonia performed a vocal part in Italian Eurobeat singer Nuage's "I'm Never Gonna Let You Down and Forget You", released in Japan in 2004, produced by Dave Rodgers.

In 2007, prior to Sonia's Greatest Hits release, she recorded two Motown-influenced songs, "Dancing in the Driver's Seat" and "Your Heart or Mine", both of which were written by Barry Upton and U.S. songwriter Gordon Pogoda.

Also in 2010, Sonia's cover version of "You've Got a Friend", a duet with Big Fun, was released on a reissue of the group's debut album.

On 21 December 2012, Sonia performed at the Stock Aitken Waterman "Hit Factory Live" reunion concert at The O2 in London, along with many other former SAW acts, including Kylie Minogue.

[10] In summer 2018, in conjunction with her appearance in the Channel 5 program Celebrity 5 Go Caravanning, Sonia's recording of "Dancing in the Driver's Seat", written by Barry Upton and Gordon Pogoda, was released.

[11] In 2018, Sonia appeared alongside Todd Carty, Tony Blackburn, Colin Baker and Sherrie Hewson in Channel 5's Celebrity 5 Go Caravanning.

Sonia made a significant guest appearance as herself in Channel 4 soap opera, Hollyoaks, in the episode aired Friday, 12 May 2023.

This is a reference to Fletcher's previous long-running role in Brookside, as Jacqui Dixon (from 1990 to 2003, produced by the same production company, and in which, Sonia herself was an extra in 1988), whose father, Ron, ran a mobile mini-market from a blue van with a white whale painted down the side called The Moby Dick.