The MAGIC collaboration reports the discovery of very high energy (VHE ; E>100 GeV) gamma-ray emission from the FSRQ S4 0954+65 (RA=+9:58:47.00, DEC=+65:33:55.00, J2000.0), located at redshift z=0.368. The object was observed with the MAGIC telescopes for ~2 hours during the night 2015 February 13/14 (MJD 57067). A preliminary analysis of the data yields detection with a statistical significance of more than 5 standard deviations. This is the first time a significant signal at VHE gamma rays has been seen from S4 0954+65. The flux above 150GeV is estimated to be about 2e-11 cm^-2 s^-1. S4 0954+65 is entered an exceptionally high state at optical and near infrared frequencies (ATels #7057 ; #7055 ; #7046, #7001 ; #6996), which triggered the MAGIC observations. Optical observations performed with the KVA telescope suggests that this is the brightest state ever observed from this source since November 2006 (beginning of KVA observations). The preliminary lightcurve is available at: http://users.utu.fi/kani/1m/S4_0954+65.html. During the preparation of this ATel, we were informed by Fermi-LAT collaboration that the gamma-ray flux above 100 MeV from S4 0954+65 also increased substantially during the last few days. MAGIC observations on S4 0954+65 will continue during the following nights, and multiwavelength observations are encouraged. The MAGIC contact persons for these observations are R. Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de) and E. Lindfors (elilin@utu.fi). MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV.