Elton John threw the grand finale of husband David Furnish’s 50th birthday at the opening of Simon Hammerstein’s The Act in Las Vegas on Saturday. Elton brought in 120 friends from LA on luxury buses to the new venue at The Shoppes at the Palazzo. Other celebs included Susan Sarandon in a purple wig, Malin Akerman, “Mad Men” bombshell Christina Hendricks (who is a fan of Hammerstein’s The Box in New York), her co-star Michael Gladis, “Glee” star Mark Salling and Pussycat Dolls creator Robin Antin. It was the highlight of Furnish’s epic birthday celebrations that started last Thursday at Hollywood’s Belasco Theater with guests including Johnny Depp.