Demi Lovato reunites with ex Joe Jonas for concert duet

Demi Lovato proved she has nothing but love for ex-boyfriend Joe Jonas on Tuesday night (26Jul16) by inviting him onstage for a duet in Washington, D.C.

The former Disney co-stars dated briefly in early 2010, months before Demi suffered a very public breakdown while on tour in South America with The Jonas Brothers, but the pair has since become good friends, with Joe recently praising his ex for becoming the "best version of herself" after conquering her personal demons.

On Tuesday, the former lovers revisited their past by teaming up to sing This Is Me, a tune featured in their TV movie Camp Rock, which also starred Joe's Jonas Brothers bandmates and siblings Kevin and Nick.

Nick, who is currently on a joint tour with Demi, also joined in the fun by backing them on guitar.

Joe wasn't Demi's only special guest at the Future Now gig - she also brought out country star Brad Paisley to join her for a rendition of their recent collaboration Without a Fight, as well as the 23-year-old's ballad Stone Cold.

The two unlikely collaborators were paired up to perform Stone Cold at the iHeartRadio Music Awards earlier this year (16), and the get together inspired Brad to write Without a Fight for himself and his new pal to sing together.

The duo performed the new track live together for the first time in May (16), when Demi surprised gig-goers at Paisley's concert in Irvine, California.

After the show in Washington, D.C., Brad took to Twitter to share a couple of photos of the stars onstage, captioning one snap, "Honored to be here @ddlovato #withoutafight D.C."