"Be still my heart -- she is a class act -- what a way to finish my week on Kimmel," the comedian says of the singer's message.

Rosie O'Donnell and Barbra Streisand backstage at Barbra Streisand in Concert, October 11th, 2006 at Madison Square Garden in New York City, New York, United States.

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Rosie O’Donnell’s return to late-night television just got a meaningful stamp of approval from one of her longtime idols: Barbra Streisand.

During O’Donnell’s guest-hosting stint on Jimmy Kimmel Live! this week, Streisand reached out with a short but incredibly sweet message to celebrate the comedian’s return to television. O’Donnell shared a screenshot via Instagram on Thursday (Aug. 20), giving her audience a peek at the unexpected note.