Taylor Swift invited Tegan and Sara on stage with her earlier this week.
The 'I Knew You Were Trouble' hitmaker was joined by the duo to sing their track 'Closer' at one of the show in the Los Angeles leg of her Red Tour at the city's Staples Center on Tuesday (20.08.13).
Taylor praised the duo's LP 'Heartthrob' as one of her "favourites of all time" before introducing them to screaming fans at the sold-out venue.
The 23-year-old - who split from One Direction's Harry Styles earlier this year - said: "If you've ever had your heart broken, you need to have their album."
Taylor's surprise guests come after she was joined onstage by British popstar Cher Lloyd to perform the singer's 2012 track 'Want You Back' on Monday night (19.08.13) in addition to special appearances from Sara Bareilles and her support artist Ed Sheeran.
The country-pop sensation will perform her fourth sell-out show at the 18,000 capacity venue on Saturday (24.08.13) after which she'll claim the record for the solo artist with the most sell outs gigs at the Los Angeles venue, with 11 to date, tying her with Latin pop group Mana.
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