Taylor Swift is reportedly planning a huge birthday celebration in Australia with her boyfriend and best friends. The singer will turn 26 on December 13, just one day after she wraps up her '1989' world tour in Melbourne and will fly her beau Calvin Harris and many members of her girl squad to Hamilton Island, Queensland for a lavish bash. Selena Gomez and Karlie Kloss are expected at the party, along with stars including Oprah Winfrey and Ed Sheeran, according to Australia's Daily Telegraph. Taylor celebrated her 24th birthday with a garden party in Melbourne. Meanwhile, Selena, 23, recently revealed that she turns to Taylor for romantic advice. Selena, who split from her boyfriend Justin Bieber last year following almost four years of on/off dating, has admitted she automatically turns to the 25-year-old starlet when she needs help in the "boy department." Speaking to Britain's InStyle magazine, she said: "I'll be like, 'I think I totally screwed up,' but Taylor says, 'Actually, you didn't,' and shows me how to make my mistakes into something great. People have this fantasy that we're in our underwear, having pillow fights. We just play good music - sometimes live - and eat, and hang out."