(TMZ) The mother of 5-year-old "Toddlers & Tiaras" star Isabella Barrett doesn't care that her daughter's performing LMFAO's "Sexy and I Know It" in nightclubs -- telling TMZ, "That's a real catchy song!"Susanna Barrett was out shopping with her daughter yesterday in NYC -- telling us, Isabella's a big fan of top 40 music ... and that's why she was able to spout off the LMFAO lyrics at a New York nightclub this week. According to Susanna, Isabella also loves Lady Gaga and Rihanna.
But Susanna quickly pointed out ... there are limits -- for instance, Isabella has never seen the music video for "Sexy and I Know It" ... which shows the lead singer shaking his man-package around in a Speedo... see it here.
