DeVito, who was sitting in the stalls of the Adelphi Theatre, stepped in to provide some entertainment when the screen-to-stage musical was stopped due to technical problems.
Cast member and Whatsonstage.com nominee Debbie Kurup tweeted: "Tonight's show was interesting! Show stop for 35 mins so Danny DeVito - who happens to be watching, gets up to entertain the audience!"
A representative of the show told Whatsonstage.com: "It was Thea's birthday so Heather Headley got the audience to sing to her. She then got up on stage, bringing Danny with her, who kept everybody entertained."
The interruption occured during Act One, and lasted for over half an hour. "Everybody loved the break and were on their feet by the end," added the representative.
The Bodyguard is nominated in six categories in the 2013 Whatsonstage.com Awards. For full shortlists and to vote, click here