The field of extrasolar planets has become one of the most lively and vibrant field of research in astrophysics. As is almost always the case in astrophysics, a multi-wavelength approach is required to fully explore and understand the properties of those planets. Also, X-ray astronomy plays an important role in this process. The host stars of essentially all extrasolar planets are (sometimes very vigorous) X-ray emitters, which can severely impact on the outer atmospheric layers of their planets. Furthermore, the close proximity between host stars and planets in the case of close-in ``Hot Jupiters{''} may lead to magnetic or tidal interactions with observable consequences at X-ray wavelengths. I will address these issues and discuss how XMM-Newton can be used to advance the field.